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Background: In the randomized, phase 3, SUSA-301 trial, celecoxib-tramadol co-crystal (CTC) provided significantly greater analgesia compared with celecoxib, tramadol, or placebo in adults with acute, moderate-to-severe, postoperative pain. This post hoc, secondary analysis further evaluated the use of rescue medication and the incidence of treatment-emergent adverse events (TEAEs)., Methods: Patients (N = 637) were randomized 2:2:2:1 to receive oral CTC 200 mg twice daily (BID; n = 184), tramadol 50 mg four times daily (QID; n = 183), celecoxib 100 mg BID (n = 181), or placebo QID (n = 89). Post hoc analyses were conducted on the use of rescue medications up to 4 and 48 h post-study drug dose, stratified by baseline pain intensity (moderate/severe), and on the incidence of TEAEs, stratified by rescue medication use., Results: A significantly lower proportion of patients received any rescue medication within 4 h post-study dose with CTC (49.5%) versus tramadol (61.7%, p = 0.0178), celecoxib (65.2%, p = 0.0024), and placebo (75.3%, p = 0.0001); this was also seen for oxycodone use. Fewer patients in the CTC group received ≥3 doses of rescue medication compared with the other groups, irrespective of baseline pain intensity. In patients who did not receive opioid rescue medication, CTC was associated with a lower incidence of nausea and vomiting TEAEs versus tramadol alone. In patients who received rescue oxycodone, the incidence of nausea was similar in the CTC and tramadol groups, and higher versus celecoxib and placebo., Conclusion: Celecoxib-tramadol co-crystal was associated with reduced rescue medication use and an acceptable tolerability profile compared with tramadol or celecoxib alone in adults with acute, moderate-to-severe, postoperative pain., (© 2024 Esteve Pharmaceuticals S.A and The Author(s). Pain Practice published by Wiley Periodicals LLC on behalf of World Institute of Pain.)

Multimodal analgesia is defined as using several drugs or techniques simultaneously to target different pain pathways or receptors to avoid pain propagation. This study evaluated the pharmacokinetic profile and comparative bioavailability of etoricoxib 90 mg and tramadol 50 mg dosing alone (reference drugs) or in a novel fixed-dose combination (test drug) under fasting conditions in Mexican healthy volunteers. This was a randomized, open-label, 3-way, crossover, single-dose, prospective, and longitudinal study with a 14-day washout period. Eligible subjects were healthy Mexican adult volunteers. The drugs were dosing orally, according to the randomization sequence, after 10 hours of fasting and 4 hours before breakfast with 250 mL of water at room temperature. Serial blood samples were collected before and after dosing, both drugs were quantified using high-performance liquid chromatography coupled with tandem mass spectrometry. Forty-two subjects were enrolled and 38 completed the study (28 men and 14 women, mean age 25.2 years, mean weight 66.6 kg). Test products were considered to have comparative bioavailability if confidence intervals of natural log-transformed for (maximum plasma drug concentration (C max ), (area under the plasma drug concentration-time curve form 0 up to last sampling time (AUC 0-t ), and (area under the plasma drug concentration-time curve from 0 up to infinity (AUC 0-∞ ) data were within the range of 80%-125%. Non-serious adverse events were observed. The results demonstrate that the pharmacokinetic profile and bioavailability of the etoricoxib/tramadol fixed-dose combination are comparable to those of the reference products., (© 2024 Laboratorios Silanes. Clinical Pharmacology in Drug Development published by Wiley Periodicals LLC on behalf of American College of Clinical Pharmacology.)

Objectives: This study aims to determine the usage pattern, effectiveness and safety of oral tramadol 75 mg and dexketoprofen trometamol 25 mg fixed-dose combination (TRAM/DKP FDC) in the short-term treatment of moderate-to-severe acute pain in real-world clinical practice in Asia., Design: Real-world, prospective, multicentre, observational, phase IV study., Setting: 13 tertiary-care hospital sites across the Philippines, Thailand, Malaysia and Singapore., Participants: Adult patients aged 18-80 years prescribed TRAM/DKP FDC for the short-term (up to 5 days) treatment of moderate-to-severe acute pain., Main Outcome Measures: Primary endpoints were the proportion of patients prescribed TRAM/DKP FDC with different types of postsurgical and non-surgical treatments, and the average dosing frequency and duration of TRAM/DKP FDC treatment. Secondary endpoints were the proportion of patients achieving ≥30% pain reduction at 8 hours post the first dose (pain severity was assessed using the 11-point Numeric Pain Rating Scale); patient satisfaction at the end of treatment (based on a 5-point Patient Global Evaluation Scale (PGE)) and safety including the incidence of adverse drug reactions (ADRs)., Results: Among 599 patients (median age 44 years, 61.3% female) enrolled in this study, 68.61% (n=411) were postsurgical and 31.39% (n=188) were non-surgical patients. TRAM/DKP FDC was prescribed in a diverse group of postsurgical patients (eg, orthopaedic, general and cancer surgery) as well as in non-surgical conditions (eg, lower back pain and musculoskeletal pain). In the majority of patients, TRAM/DKP FDC was prescribed every 8 hours (65.94%) and for 5 days (78.80%). There was a significant reduction in pain intensity throughout the study and 65% of patients achieved ≥30% pain reduction from baseline at 8 hours post the first dose of TRAM/DKP FDC on day 1. 95.69% of patients were satisfied with the treatment (rated good, very good and excellent on the PGE scale). Overall, 13.9% of patients reported ADRs; most were mild to moderate in severity. The most common ADRs were nausea, vomiting and dizziness., Conclusion: This study showed that TRAM/DKP FDC was used in diverse types of postsurgical and non-surgical patients in the real-world setting in Asia. It effectively reduced pain and was well tolerated with a high level of patient satisfaction., Competing Interests: Competing interests: BG, AG and DN are employees of A. Menarini Asia-Pacific Holdings Pte. Ltd., Singapore. All other authors report receiving investigator fees for this study from the sponsor., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Introduction: Tramadol has been associated with chronic opioid use and emergency room (ER) visits. However, little is known about trends in prescription tramadol use in the U.S., Methods: Optum's de-identified Clinformatics® Data Mart Database was used to assess trends in monthly incident and prevalent tramadol use from 2005 to 2021, stratified by sex and age (18-64 vs. ≥65 years). State-specific trends following scheduling of tramadol as Class IV controlled substance in August 2014 were analyzed with random effects regression models. Demographics, comorbidities, initiation setting, dose, and co-dispensing with other opioids and central nervous system (CNS) agents were assessed in people initiating tramadol, stratified by age and initiation year (2005-2010, 2011-2015, 2016-2021). Analyses were performed in 2023 and 2024., Results: During 2005-2021, the mean percentage using tramadol in a given month was 0.88% of younger females, 0.55% of younger males, 1.97% of older females, and 1.14% of older males; 5,729,652 initiations were identified. Since 2014, estimated relative yearly decrease was 4% (95% CI 3%; 5%) in use and 5% (95% CI 4%; 5%) in initiation, with variation across states. Primary care percentage of tramadol initiations declined from 49.2% in 2005-2010 to 37.2% in 2016-2021. During 2016-2021, co-dispensing with other CNS agents occurred in 37.8% of younger and 32.1% of older adults initiating tramadol., Conclusions: Tramadol use was higher in females and older adults, exhibited heterogeneous trends across states, and shifted from primary care to ER and specialist settings over time. Co-dispensing with other CNS agents was common and warrants further monitoring., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: Post-operative pain control improves patient's satisfaction and affects the period of admission. Local wound infiltration following hernia surgery using xylocaine or bupivacaine has been a common practice. The use of tramadol for such infiltration is relatively new and has not been studied in our environment. This study compared the efficacy of post-operative pain control between Bupivacaine and Tramadol wound infiltration in children who underwent herniotomy and orchidopexy., Materials and Methods: This was a prospective randomised study involving 104 patients. A simple random method was used to allocate the study group into two equal groups (A, n = 52 and B, n = 52) using sealed envelopes with contents labelled A or B. Pre- and post-operative respiratory rate, heart rate, and C-reactive protein (CRP) were all recorded. Time to first and subsequent analgesia was determined using face, legs, activity, cry, consolability (FLACC) pain score., Results: Fifteen patients in Group A and 18 patients in Group B received each two doses of supplemental analgesia within the first 24 h, ( P = 0.527). Time to first analgesia was significantly different between the two groups, (6.93 ± 0.80 h and 6.11 ± 1.08 h, P = 0.020). The mean FLACC pain score at the time of first analgesia in hours was 4.93 ± 0.59 and 4.72 ± 0.67 for Group A and B, respectively, P = 0.350. The changes in CRP were not different in the two groups, ( P = 0.665). Four patients in Group A, but none in Group B had an episode each of post-operative vomiting., Conclusion: Tramadol showed comparable efficacy with bupivacaine in post-operative pain control by wound infiltration in children who had unilateral herniotomy or orchidopexy. Tramadol, however, achieves a longer duration of action before rescue analgesic is required. Caution is necessary to avoid post-operative vomiting., (Copyright © 2024 Copyright: © 2024 African Journal of Paediatric Surgery.)

Tramadol is a weak opioid used to treat moderate pain. Stronger opioids inhibit gastrointestinal function, but little is known about the gastrointestinal effects of tramadol. Our aim was to investigate if tramadol causes opioid-induced bowel dysfunction (OIBD). Twenty healthy male participants (mean age 24 [range 20-31] years) were included. Tramadol (extended-release formulation, 200 mg/day) or placebo was administered for 10 days in two study periods separated by 3 weeks. Gastrointestinal transit times and segmental volume, motility and water content were investigated with the 3D-transit system and magnetic resonance imaging. Bowel movements and gastrointestinal symptoms were recorded daily. Tramadol prolonged colonic transit time (34 h vs. 25 h, p < 0.001) and increased small bowel motility (p < 0.01) and water content (p = 0.002) compared to placebo. Across all days of treatment, tramadol reduced the number of mean daily bowel movements (p = 0.001) and increased mean stool consistency (p = 0.006). Gastrointestinal symptom scores increased with tramadol (indigestion: +358%, p = 0.01; constipation: +475%, p = 0.01). Additionally, more participants fulfilled the diagnostic criteria for constipation after tramadol treatment compared to placebo (40% vs. 0%, p < 0.001). This study showed that tramadol treatment is associated with OIBD, and management of constipation and other bowel symptoms should, therefore, be prioritised when treating pain patients with tramadol., (© 2024 The Author(s). Basic & Clinical Pharmacology & Toxicology published by John Wiley & Sons Ltd on behalf of Nordic Association for the Publication of BCPT (former Nordic Pharmacological Society).)

We aimed to examine the efficacy of combination therapies of Neurotropin® with tramadol and Neurotropin with mirogabalin for neuropathic pain management. A neuropathic pain model (L5 spinal nerve ligation model: L5-SNL) using male Wistar rats was generated through tight ligation of the left fifth lumbar nerve using silk sutures. Mechanical allodynia was assessed using the 50% paw withdrawal threshold. The combined antiallodynic effects were evaluated using isobolographic analyses. Small intestinal transit was evaluated using the charcoal meal test, and motor coordination using the rota-rod test. Neurotropin (50-200 NU/kg, p.o.), tramadol (7.5-60 mg/kg, p.o.), and mirogabalin (3-30 mg/kg, p.o.) showed a dose-dependent antiallodynic effect in L5-SNL rats. The combined antiallodynic effects of Neurotropin and tramadol were additive or synergistic, whereas those of Neurotropin and mirogabalin were additive. Neurotropin (100-400 NU/kg, p.o.) did not affect the small intestinal transit, whereas tramadol (30-100 mg/kg, p.o.) significantly inhibited it. Neurotropin (100-400 NU/kg, p.o.) did not affect the walking time, whereas mirogabalin (10-100 mg/kg, p.o.) significantly decreased it. Neurotropin dose-dependently ameliorated mechanical allodynia in rats, and combination therapy with Neurotropin-tramadol or Neurotropin-mirogabalin may alleviate neuropathic pain without aggravating the adverse effects of tramadol and mirogabalin., Competing Interests: Declaration of competing interest All authors are employees of Nippon Zoki Pharmaceutical Co., Ltd. The authors indicated no potential conflicts of interest., (Copyright © 2024 The Authors. Production and hosting by Elsevier B.V. All rights reserved.)

Pain is perceived not only by personal experience but also vicariously. Pain empathy is the ability to share and understand other's intentions and emotions in their painful conditions, which can be divided into cognitive and emotional empathy. It remains unclear how centrally acting analgesics would modulate brain activity related to pain empathy and which component of pain empathy would be altered by analgesics. In this study, we examined the effects of the analgesic tramadol on the brain activity for pain empathy in healthy adults. We used 2 tasks to assess brain activity for pain empathy. In experiment 1, we used a well-established picture-based pain empathy task involving passive observation of other's pain. In experiment 2, we developed a novel pain empathy task to assess brain activity during cognitive and emotional empathy for pain separately in a single task. We conducted a double-blind, placebo-controlled within-subject crossover study with functional magnetic resonance imaging for 33 participants in experiment 1 and 31 participants in experiment 2, respectively. In experiment 1, we found that tramadol decreased activation in the supramarginal gyrus during observation of other's pain compared with placebo. Supramarginal gyrus activation correlated negatively with the thermal pain threshold. In experiment 2, we found that tramadol decreased activation in angular gyrus in cognitive empathy for pain compared with placebo but did not change brain activity in emotional empathy for pain. PERSPECTIVE: Centrally acting analgesics such as tramadol may have not only analgesic effects on self-experienced pain but also on the complex neural processing of pain empathy., (Copyright © 2024 United States Association for the Study of Pain, Inc. Published by Elsevier Inc. All rights reserved.)

Objective: To investigate the effects of pregabalin combined with tramadol/paracetamol on acute pain in patients with CT-guided puncture localization of pulmonary nodules., Materials and Methods: In this randomized, placebo-controlled and single-center study, 120 patients were allocated randomly to four groups: the control group (Group P), the pregabalin-placebo group (Group BP), the tramadol/paracetamol-placebo group (Group AP), and the pregabalin-tramadol/paracetamol group (Group AB). The primary outcome was the NRS (Numerical Rating Scale) score. Other outcomes included systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR), pulse oxygen saturation (SpO 2 ), the incidence of moderate to severe pain, the analgesia recovery ratio, the incidence of adverse drug reactions and patients' satisfaction., Results: No significant interaction was detected between the interventions (P = 0.752). The NRS score of the Taking pregabalin group and the Taking tramadol/paracetamol group were significantly lower than those of the Not-taking pregabalin group and the Not-taking tramadol/paracetamol group respectively (P < 0.05). There was significant difference in the NRS scores among the four groups (P < 0.001). The NRS score of Group AB was significantly lower than that of Group P (P < 0.001), Group BP (P < 0.001) and Group AP (P = 0.001). At the same time, the NRS scores of Group BP (P < 0.001) and Group AP (P < 0.001) were significantly lower than those of Group P, but there was no significant difference between Group BP and Group AP (P = 1.000). The SBP, DBP, HR, the incidence of moderate to severe pain and the analgesia recovery ratio of Group AB were significantly lower than those of Group P (P < 0.05), while the SpO 2 and the number of people who were very satisfied were significantly higher than those of Group P (P < 0.05). There was no significant difference in the incidence of adverse drug reactions among the four groups (P = 0.272)., Conclusions: The combination or single use of pregabalin and tramadol/paracetamol can effectively relieve the acute pain after localization. Pregabalin combined with tramadol/paracetamol has the best analgesic effect and significantly reduces the hemodynamic fluctuations, with high safety and low incidence of adverse drug reactions, which has a certain clinical popularization and application value., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The multimodal analgesia strategy for acute pain involves using 2 or more analgesic medications with distinct mechanisms of action. This study assessed the bioavailability and tolerability of 2 tramadol hydrochloride (50 mg)/diclofenac sodium (50 mg) fixed-dose combination formulations under fed conditions to attend the Brazilian regulatory requirements for generic product registration. An open-label, randomized, single-dose, 2-period, 2-way crossover trial was conducted, including healthy subjects of both sexes. Subjects received a single dose of either the test or reference formulation of tramadol/diclofenac fixed-dose combination tablets with a 7-day washout period. Blood samples were collected up to 36 hours after dosing for tramadol and 12 hours for diclofenac and quantified using a validated liquid chromatography-tandem mass spectrometry method. Of 56 subjects enrolled, 53 completed the study. The 90% confidence intervals for maximum plasma concentration and area under the concentration-time curve from time 0 to the last quantifiable concentration were within acceptable bioequivalence limits of 80%-125%. Considering the results presented in this study, the test formulation is bioequivalent to the reference formulation and could be interchangeable in medical practice., (© 2024 The Authors. Clinical Pharmacology in Drug Development published by Wiley Periodicals LLC on behalf of American College of Clinical Pharmacology.)

Aim: To evaluate tramadol hydrochloride, an atypical opioid with potential analgesic properties, as a viable alternative to lignocaine hydrochloride in supraperiosteal anesthesia for dental implants., Materials and Methods: A split-mouth, double-blind, randomized controlled trial was conducted in patients requiring maxillary dental implants. Patients meeting inclusion criteria received either 5% tramadol hydrochloride with adrenaline or 2% lignocaine hydrochloride with adrenaline via supraperiosteal infiltration. Onset, duration of anesthesia, visual analog scale (VAS) pain scores, and adverse effects were recorded., Results: Forty patients were included, with a mean age of 39.35 years, 62.5% male. No significant differences were observed in VAS pain scores between tramadol (2.08 ± 1.328) and lignocaine (2.05 ± 1.260) groups ( p = 0.931). Onset of anesthesia showed no significant difference between the tramadol (128.00 ± 18.207 seconds) and lignocaine (128.30 ± 18.287 seconds) groups ( p = 0.736). The duration of anesthesia was comparable between tramadol (59 ± 12.092 minutes) and lignocaine (59.90 ± 11.705 minutes) groups ( p = 0.0736). Adverse effects included nausea in two tramadol and one lignocaine patient., Conclusion: Tramadol hydrochloride demonstrated comparable local anesthetic efficacy to lignocaine hydrochloride in dental implant surgery Clinical significance: Both drugs provided effective pain control with similar onset and duration of anesthesia. Tramadol may offer an alternative for patients with lignocaine contraindications, although further studies are warranted to validate its safety and efficacy in dental procedures. How to cite this article: Parlawar AN, Mundada BP. Assessing Tramadol Hydrochloride as an Alternative to Lignocaine Hydrochloride in Dental Implant Procedures: A Randomized Trial. J Contemp Dent Pract 2024;25(7):639-644.

Objective: To explore preemptive analgesic effect of preoperative intramural tramadol injection in percutaneous kyphoplasty (PKP) of vertebrae following local anesthesia., Methods: From August 2019 to June 2021, 118 patients with thoraco lumbar osteoporotic fractures were treated and divided into observation group and control group, with 59 patients in each gruop. In observation group, there were 26 males and 33 females, aged from 57 to 80 years old with an average of (67.69±4.75)years old;14 patients on T 11 , 12 patients on T 12 , 18 patients on L 1 , 15 patients on L 2 ;tramadol with 100 mg was injected intramuscularly half an hour before surgery in observation group. In control group, there were 24 males and 35 females, aged from 55 to 77 years old with an average of (68.00±4.43) years old;19 patients on T 11 , 11 patients on T 12 , 17patients on L 1 , 12 patients on L 2 ;the same amount of normal saline was injected intramuscularly in control group. Observation indicators included operation time, intraoperative bleeding, visual analogue scale (VAS) evaluation and recording of preoperative (T0), intraoperative puncture(T1), and working cannula placement (T2) between two groups of patients, at the time of balloon dilation (T3), when the bone cement was injected into the vertebral body (T4), 2 hours after the operation (T5), and the pain degree at the time of discharge(T6);adverse reactions such as dizziness, nausea and vomiting were observed and recorded;the record the patient's acceptance of repeat PKP surgery., Results: All patients were successfully completed PKP via bilateral pedicle approach, and no intravenous sedative and analgesic drugs were used during the operation. There was no significant difference in preoperative general data and VAS(T0) between two groups ( P >0.05). There was no significant difference in operation time and intraoperative blood loss between the two groups ( P >0.05). VAS of T1, T2, T3, T4 and T5 in observation group were all lower than those in control group( P <0.05), and there was no significant difference in T6 VAS ( P >0.05). T6 VAS between two groups were significantly lower than those of T0, and the difference was statistically significant ( P <0.05). There was no significant difference in incidence of total adverse reactions between two groups ( P >0.05). There was a statistically significant difference in the acceptance of repeat PKP surgery ( P <0.05)., Conclusion: Half an hour before operation, intramuscular injection of tramadol has a clear preemptive analgesic effect for PKP of single-segment thoracolumbar osteoporotic fracture vertebral body under local anesthesia, which could increase the comfort of patients during operation and 2 hours after operation, and improve patients satisfaction with surgery.

Background: With the rising toll of the opioid crisis, oculoplastic surgeons have been looking at methods to decrease opioid prescription., Objectives: The aim of this study was to identify factors that correlate with opioid usage after oculoplastic surgery., Methods: This was a prospective study conducted at University of Texas Southwestern. All patients who underwent an oculoplastic procedure were eligible for inclusion. Patients enrolled were provided 20 tablets of tramadol 50 mg, to take 1 tablet every 6 hours as needed for pain. At their postoperative week 1 appointment, participants had the remaining number of unused opioid tablets counted. The number of tablets taken were calculated by subtracting the remaining number of tablets from the original prescribed amount., Results: A total of 310 patients were enrolled in our study. Of these, 129 patients met the inclusion criteria. There was a statistically significant difference in the number of tramadol tablets taken between procedures for upper eyelids, lower eyelids, and both eyelids (P < .01). There were no statistically significant differences in tramadol usage when comparing procedures on eyelids with orbit procedures(P = .30), cosmetic with noncosmetic procedures (P = .52), males with females (P = .87), or patients naive to oculoplastic procedures with those undergoing reoperation (P = .58). Longer procedures were correlated with greater tramadol usage (R = 0.28, P < .01)., Conclusions: This is the first study in the literature that has objectively quantified opioid usage after oculoplastic surgery in a prospective manner. Procedures that involve both upper and lower eyelids simultaneously and longer procedures resulted in higher opioid use. Orbital procedures, cosmetic procedures, sex, and procedural naivety were not found to be associated with higher opioid usage., (© The Author(s) 2024. Published by Oxford University Press on behalf of The Aesthetic Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background and Objectives: New acute pain medications are needed that provide effective analgesia while minimizing side effects and opioid exposure. Clinical trials of co-crystal of tramadol-celecoxib (CTC) have demonstrated an improved benefit/risk profile versus tramadol or celecoxib alone. We pooled data from two phase 3 clinical trials to evaluate the efficacy of CTC 200 mg twice daily (BID) in acute moderate-to-severe pain., Methods: Efficacy data were pooled from STARDOM1 [acute pain following oral surgery (NCT02982161)] and ESTEVE-SUSA-301 [acute pain following bunionectomy (NCT03108482)]. The primary efficacy outcome was sum of pain intensity difference from 0 to 48 h (SPID 0-48 )., Results: A total of 344 patients received CTC 200 mg BID, 342 received tramadol 50 or 100 mg four times a day, 181 received celecoxib 100 mg BID, and 172 received placebo. The least-squares mean difference in SPID 0-48 was -21.8 (p = 0.002) for CTC versus tramadol and -72.8 (p < 0.001) for CTC versus placebo. A similar pattern of SPID 0-48 was observed with CTC versus comparator whether patients had moderate or severe pain at baseline. Reduction in pain intensity was faster and reached mild intensity earlier with CTC versus comparators. Patients were significantly (p ≤ 0.005) less likely to receive rescue medication within 4 or 48 h with CTC compared with tramadol or placebo., Conclusions: This pooled analysis reinforces the efficacy profile of CTC versus tramadol and, given that CTC permits lower daily tramadol dosing and thereby reduces unnecessary opioid use, this highlights its improved benefit/risk profile and its potential for the management of moderate-to-severe pain., (© 2024. The Author(s).)

Purpose: To assess the efficacy and safety of perioperative parenteral administration or submucosal infiltration of tramadol for perioperative pain control on the basis of pain intensity or analgesics consumption and perioperative outcomes in mandibular third molar surgery., Material-Methods: An electronic database search was conducted up to 10 November 2022 to retrieve all randomized controlled trials (RCTs), assessing the analgesic efficacy of parenteral use of tramadol implemented as an adjunct to local anesthesia or intraoperative sedation/general anesthesia, in surgical extraction of mandibular third molars. Modified Jadad scale and Cochrane bias tool were used for the qualitative appraisal., Results: Nineteen RCTs were selected for qualitative analysis. Nine studies involved intravenous, and 5 intramuscular administration of tramadol, while 5 evaluated submucosal infiltration with tramadol. Intravenous or intramuscular tramadol provided a weaker analgesic effect compared with non-steroidal anti-inflammatory drugs (NSAIDs), while intravenous tramadol induced an enhanced analgesic effect than oral tramadol. Parenteral administration of tramadol improved the quality of postoperative analgesia versus placebo. No notable adverse effects were recorded., Conclusions: Parenteral or submucosal infiltration of tramadol constitutes an effective and safe alternative analgesic approach in surgical extraction of mandibular third molars, yet the nociceptive effect of this analgesic modality could not supersede that of NSAIDs., Trial Registration: PROSPERO No CRD42021227574., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Objectives: Multimodal pain management is one component in enhanced recovery after surgery protocol. Here we evaluate the efficacy of tramadol-paracetamol in acute postoperative pain and pain outcome at 12 months after spine surgery in randomized, double-blind, placebo-controlled trial., Methods: We randomized 120 patients undergoing spine surgery to receive, for add-on pain management, two tramadol-paracetamol 37.5 mg/325 mg ( n = 61) or placebo tablets ( n = 59) twice a day for 5 postoperative days. In the hospital, multimodal pain management consisted of dexketoprofen and oxycodone. After discharge, patients were prescribed ibuprofen 200 mg, maximum 1,200 mg/day. Pain, analgesic use, and satisfaction with pain medication were followed up with the Brief Pain Inventory questionnaire before surgery and at 1 and 52 weeks after surgery. The primary outcome was patients' satisfaction with pain medication 1 week after surgery., Results: At 1 week after surgery, patients' satisfaction with pain medication was similarly high in the two groups, 75% [interquartile range, 30%] in the placebo group and 70% [40%] in the tramadol-paracetamol group ( p = 0.949) on a scale: 0% =  not satisfied, 100% = totally satisfied. At 1 week, ibuprofen dose was lower in the placebo group 200 mg [1,000] compared to the tramadol-paracetamol group, 800 mg [1,600] ( p = 0.016). There was no difference in the need for rescue oxycodone. Patients in the tramadol-paracetamol group had more adverse events associated with analgesics during the first postoperative week (relative risk = 1.8, 95% confidence interval, 1.2-2.6)., Conclusion: Add-on pain treatment with tramadol-paracetamol did not enhance patients' satisfaction with early pain management after back surgery., (© 2024 the author(s), published by De Gruyter.)

Background: Multimodal analgesia for total hip arthroplasty (THA) is increasingly employed to reduce early postoperative pain and promote fast patient discharge. The aim of this study was to compare the efficacy and tolerability of tramadol/dexketoprofen (TRAM/DKP, Group A) versus paracetamol + tramadol (PARA+TRAM, Group B) in patients undergoing THA using minimally invasive direct anterior approach (DAA)., Methods: A single-centre, randomised, single-blind, parallel, interventional study conducted in 323 patients undergoing primary THA with DAA was performed. Group A consisted of 188 patients and Group B of 135. The primary endpoints were the change from baseline (measured 2 hours postoperatively) in pain intensity (PI) during the treatment period (48 hours), assessed by visual analogue scale (VAS) at pre-specified postoperative time-points (2, 8, 24, 48 hours) and the total rescue medication (RM) use during the first 24 hours postoperatively., Results: As early as 2 hours after baseline, Group A showed a greater PI reduction from baseline compared to Group B (-26.24% vs. -6.87%; p   <  0.001). A lower mean PI (VAS) score was consistently found over the entire observation period following treatment with TRAM/DKP than with PARA+TRAM as well as more than 2-fold higher proportion of responders at the end of treatment period. More patients in Group B required RM in comparison to those in Group A (15.6% vs. 3.7%, p   <  0.001). Both treatments were well tolerated., Conclusions: After THA, oral TRAM/DKP provides faster and greater pain relief when compared to intravenous PARA+TRAM with limited consumption of RM and favourable tolerability profile. Our study expands the use of TRAM/DKP in the setting of major orthopaedic surgeries., Clinical Trial Registration: clinicaltrials.gov (NCT04178109)., Competing Interests: Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Objective: Erector spinae plane block is an updated method than paravertebral block, possessing a lower risk of complications. This study aimed to compare erector spinae plane and paravertebral blocks to safely reach the most efficacious analgesia procedure in laparoscopic cholecystectomy cases., Methods: The study included 90 cases, aged 18-70 years, classified as American Society of Anesthesiologists I-II, who underwent an laparoscopic cholecystectomy procedure. They were randomly separated into three groups, namely, Control, erector spinae plane, and paravertebral block. No block procedure was applied to Control, and a patient-controlled analgesia device was prepared containing tramadol at a 10 mg bolus dose and a 10-min locked period. The pain scores were recorded with a visual analog scale for 24 h postoperatively., Results: The visual analog scale values at 1, 5, 10, 20, and 60 min at rest and 60 min coughing were found to be significantly higher in Control than in paravertebral block. A significant difference was revealed between Control vs. paravertebral block and paravertebral block vs. erector spinae plane in terms of total tramadol consumption (p=0.006). Total tramadol consumption in the first postoperative 24 h was significantly reduced in the paravertebral block compared with the Control and erector spinae plane groups., Conclusion: Sonography-guided-paravertebral block provides sufficient postoperative analgesia in laparoscopic cholecystectomy surgery. Erector spinae plane seems to attenuate total tramadol consumption.

Objective: A new block, namely, modified thoracoabdominal nerves block through perichondrial approach, is administered below the costal cartilage. We sought to compare the analgesic efficacy of the modified thoracoabdominal nerves block through perichondrial approach block with local anesthetic infiltration at the port sites in an adult population who underwent laparoscopic cholecystectomy., Methods: Patients who will undergo laparoscopic cholecystectomy were randomized to receive bilateral ultrasound-guided modified thoracoabdominal nerves block through perichondrial approach blocks or local anesthetic infiltration at the port insertion sites. The primary outcome was the total amount of tramadol used in the first 12 h postoperatively. The secondary outcomes were total IV tramadol consumption for the first postoperative 24 h and visual analog scale scores., Results: The modified thoracoabdominal nerves block through perichondrial approach group had significantly less tramadol use in the first 12 h postoperatively (p<0.001). The modified thoracoabdominal nerves block through perichondrial approach group's visual analog scale scores at rest (static) and with movement (dynamic) were significantly lower compared with the port infiltration group (p<0.05)., Conclusion: Patients who received modified thoracoabdominal nerves block through perichondrial approach block had significantly less analgesic consumption and better pain scores than those who received port-site injections after laparoscopic cholecystectomy.

Calvarial craniotomy in animal models involves pain and distress. Moderate to severe pain in laboratory animals requires adequate pain management strategies. According to previous studies, the options available for suitable analgesia for rat calvarial craniotomy are very few. For most analgesic treatments, injectable routes of administration are predominantly used. However, these routes require restraining the animals, which may cause unnecessary pain, distress and suffering. As a well-fare measure, we focused on pain management by oral administration of analgesia. In this particular study, which is a sub-study of a major experiment on bone regeneration with different polymeric scaffold materials, we have compared the analgesic efficacy of intraperitoneal (I/P) and oral administration of tramadol (10 mg/kg) over a period of 96 h post-surgery in rat craniotomy models. The focus of our study is to evaluate the potential pain reduction efficacy of orally administered Tramadol without any restraining involved. We have used various non-invasive methods to assess the pain-alleviating efficacy of tramadol administered through different methods. We found that the efficacy of oral administration of tramadol is comparable to I/P administration in alleviating pain. Additionally, oral administration through drinking water has the benefit of not putting the animal under unwanted restraining stress., (© 2023. Springer Nature Limited.)

Introduction: The present study was attempted to evaluate the effect of perianal infiltration of tramadol on postoperative pain in patients undergoing hemorrhoidectomy., Method: This double-blind clinical trial study was carried out on 90 patients with grade 3 and 4 hemorrhoids undergoing hemorrhoidectomy. Patients were randomly assigned into 3 groups of control or bupivacaine or tramadol. Before the surgery, perianal infiltration of .25% bupivacaine or tramadol or normal saline was prescribed to each group, respectively. Data on pain severity (based on the visual analog scale (VAS), the duration of surgery, sedation score, pain at the first defecation, first request time for additional analgesia, nausea and vomiting, and analgesic intakes) were evaluated and analyzed., Results: Duration of surgery was almost similar in all 3 groups ( P = .974). The results showed a significant difference in pain score between 3 groups ( P ≤.05) at all times after the surgery. In addition, the means of sedation scores ( P = .03), pain score at the first defecation ( P = .001), the time to first analgesic request ( P = .001), and ketorolac administration times ( P = .01) were significantly different between 3 groups. Finally, no complication was reported regarding postoperative nausea and vomiting., Conclusion: Given the notable efficacy of tramadol in reducing pain after hemorrhoidectomy and its minor side effects, this medication is suggested as an effective topical anesthetic to decrease pain after hemorrhoidectomy.

Tramadol is among the most famous analgesic drugs used for the management, treatment and relief of moderate to severe pain conditions. The present study investigated the effects of tramadol on the behavior, mortality, morphometric, hematology and oxidative stress parameters of C. gariepinus juveniles. The 96 h LC 50 value of tramadol determined by probit analysis was 88.76 mg/L. Based on this value, fish were exposed to sublethal concentrations of 4.44, 8.88, 17.75 mg/L tramadol and 0.0 mg/L (control) for the period of 15 days and allowed to recover for 5 days. Fish exposed to tramadol showed some abnormal behavioral responses and mortality increased with increase in the exposure duration and concentrations except for the control. There were variations in hepatosomatic index (HSI) and condition factor (CF) in fish exposed to tramadol. Exposure of C. gariepinus to tramadol elicited reduction in the values of white blood cell (WBC), red blood cell (RBC), hemoglobin (Hb), packed cell volume (PCV) and mean corpuscular volume (MCV) while the values of mean corpuscular hemoglobin (MCH) and the mean corpuscular hemoglobin concentration (MCHC) increased. The values of catalase (CAT), superoxide dismutase (SOD), glutathione reductase (GR), reduced glutathione (GSH) and lipid peroxidation (LPO) increased significantly in the exposed fish compared with the control. The values of glutathione peroxidase (GPx) however decreased. The results of the present study demonstrate that tramadol is toxic to fish and its use should be monitored in the aquatic environment., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Tramadol is an opioid extensively used to treat moderate to severe pain; however, prolonged therapy is associated with several tissues damage. Chronic use of tramadol was linked to increased hospitalizations due to cardiovascular complications. Limited literature has described the effects of tramadol on the cardiovascular system, so we sought to investigate these actions and elucidate the underlying mechanisms. Mice received tramadol hydrochloride (40 mg/kg body weight) orally for 4 successive weeks. Oxidative stress, inflammation, and cardiac toxicity were assessed. In addition, eNOS expression was evaluated. Our results demonstrated marked histopathological alteration in heart and aortic tissues after exposure to tramadol. Tramadol upregulated the expression of oxidative stress and inflammatory markers in mice heart and aorta, whereas downregulated eNOS expression. Tramadol caused cardiac damage shown by the increase in LDH, Troponin I, and CK-MB activities in serum samples. Overall, these results highlight the risks of tramadol on the cardiovascular system., (© 2021. The Author(s).)

Background: Tramadol is a synthetic opioid and poisoning is increasing around the world day by day. Various treatments are applied for tramadol poisoning. Due to the unknown effects of tramadol poisoning and some of its treatments on blood glucose levels, this study was conducted to investigate the overdose of tramadol and its common treatments (naloxone, diazepam), and their combination on blood glucose levels in male rats., Methods: This study was conducted in 45 male Wistar rats. The animals were randomly divided into five groups of 9. They received a 75 mg/kg dose of tramadol alone with naloxone, diazepam, and a combination of both of these two drugs. On the last day, animals' tail vein blood glucose levels (BGL) were measured using a glucometer at different times, including before the tramadol injection (baseline) and 1 hour, 3 hours, and 6 hours after wards. The rats were anesthetized and sacrificed 24 h after the last injection. Blood samples were then taken, and the serum obtained was used to verify the fasting glucose concentration. Data were analyzed using SPSS software at a significance level of 0.05 using a one-way analysis of variance (ANOVA) and a generalized estimating equation (GEE)., Results: According to the GEE model results, the diazepam-tramadol and naloxone-diazepam-tramadol groups showed blood glucose levels five units higher than the tramadol group (p < 0.05). The diazepam-tramadol group had significantly higher blood glucose levels than the naloxone-tramadol group (p < 0.05). The mean blood glucose levels before the intervention, 3 hours and 6 hours after the injection of tramadol did not differ between the groups, but the blood glucose levels 1 hour after the injection of tramadol in the group of naloxone-tramadol were significantly lower than in the control group (p < 0.05). Blood glucose levels did not differ between the groups 24 h after injection of tramadol., Conclusion: The results of the present study showed tramadol overdose does not affect blood glucose levels. The diazepam-tramadol combination and the diazepam-naloxone-tramadol combination caused an increase in blood glucose levels., (© 2021. The Author(s).)

Objectives: To characterize the cardiopulmonary and anesthetic effects of alfaxalone at three dose rates in comparison with a ketamine-dexmedetomidine-midazolam-tramadol combination (KDMT) for immobilization of golden-headed lion tamarins (GHLTs) (Leontopithecus chrysomelas) undergoing vasectomy., Study Design: Prospective clinical trial., Animals: A total of 19 healthy, male, wild-caught GHLTs., Methods: Tamarins were administered alfaxalone intramuscularly (IM) at 6, 12 or 15 mg kg -1 , or KDMT, ketamine (15 mg kg -1 ), dexmedetomidine (0.015 mg kg -1 ), midazolam (0.5 mg kg -1 ) and tramadol (4 mg kg -1 ) IM. Immediately after immobilization, lidocaine (8 mg kg -1 ) was infiltrated subcutaneously (SC) at the incision site in all animals. Physiologic variables, anesthetic depth and quality of immobilization were assessed. At the end of the procedure, atipamezole (0.15 mg kg -1 ) was administered IM to group KDMT and tramadol (4 mg kg -1 ) SC to the other groups; all animals were injected with ketoprofen (2 mg kg -1 ) SC., Results: A dose-dependent increase in sedation, muscle relaxation and immobilization time was noted in the alfaxalone groups. Despite the administration of atipamezole, the recovery time was longer for KDMT than all other groups. Muscle tremors were noted in some animals during induction and recovery with alfaxalone. No significant differences were observed for cardiovascular variables among the alfaxalone groups, whereas an initial decrease in heart rate and systolic arterial blood pressure was recorded in KDMT, which increased after atipamezole administration., Conclusions and Clinical Relevance: Alfaxalone dose rates of 12 or 15 mg kg -1 IM with local anesthesia provided good sedation and subjectively adequate pain control for vasectomies in GHLTs. KDMT induced a deeper plane of anesthesia and should be considered for more invasive or painful procedures. All study groups experienced mild to moderate hypothermia and hypoxemia; therefore, the use of more efficient heating devices and oxygen supplementation is strongly recommended when using these protocols., (Copyright © 2021 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.)

Background and Objective: Bioequivalence tests are fundamental step in assessing the equivalence in bioavailability between a test and reference product. In practice, two separate linear mixed models (LMMs) with random subject effects, which have an area under the concentration-time curve (AUC) and the peak concentration (C max ) as the responses, have become the gold standard for evaluating bioequivalence. Recently, Lee et al developed a multivariate hierarchical generalized linear model (HGLM) for several responses that modeled correlations among multivariate responses via correlated random effects. The objective of this study was to apply this multivariate analysis to the bioequivalence test in practice and to compare the performance of multivariate HGLM and separate LMMs., Methods: Three pharmacokinetic datasets, fixed-dose combination (naproxen and esomeprazole), tramadol and fimasartan data were analyzed. We compared the 90% confidence interval (CI) for the geometric mean ratio (GMR) of a test product to a reference product using the multivariate HGLM and two conventional separate LMMs., Results: We found that the 90% CIs for the GMRs of both AUC and C max from the multivariate HGLM were narrower than those from the separate LMMs: (0.843, 1.152) vs (0.825, 1.177) for C max of esomeprazole in fixed-dose combination data; (0.805, 0.931) vs (0.797, 0.941) for C max in tramadol data; (0.801, 1.501) vs (0.762, 1.578) for C max and (1.163, 1.332) vs (1.009, 1.341) for AUC in fimasartan data, consistent with the random subject effects from two separate LMMs being highly correlated in the three datasets (correlation coefficient r = 0.883; r = 0.966; r = 0.832)., Conclusion: This multivariate HGLM had good performance in the bioequivalence test with multiple endpoints. This method would provide a more reasonable option to reduce the 90% CI by adding correlation parameters and thus an advantage especially in evaluating the bioequivalence of highly variable drugs with broad 90% CIs., Competing Interests: The authors have no conflicts of interest to disclose., (© 2021 An and Shin.)

Peripheral tramadol's delivery in the temporomandibular joint (TMJ) leads to significant analgesic outcomes and inflammatory process's resolvent actions. Mechanistically, these properties are apart from the opioid system. Nevertheless, the molecular mechanisms behind these effects are still unclear. Therefore, the present study investigated the hypothesis that adenosine A 1 receptors are involved in the tramadol-induced analgesic and anti-inflammatory effects in the TMJ. Animals were pretreated with an intra-TMJ injection of DPCPX (antagonist of A 1 receptor) or tramadol and subsequent nociceptive challenge with an intra-TMJ injection of 1.5% formalin. For over 45 min, the nociceptive behavior was quantitated, and by the end of this assessment, the animals were euthanized, and the periarticular tissue was collected. Lastly, an in vitro assay of BMDM (Bone Marrow-Derived Macrophages) was performed to investigate tramadol activity in macrophages. The intra-TMJ injection of tramadol ameliorates formalin-induced hypernociception along with inhibiting leukocyte migration. The tramadol's peripheral anti-inflammatory effect was mediated by the adenosine A 1 receptor and was associated with increased protein expression of α2a-adrenoceptor in the periarticular tissues (p < 0.05: ANOVA, Tukey's test). Also, tramadol inhibits formalin-induced leukocyte migration and protein expression of P2X7 receptors in the periarticular tissue (p < 0.05); however, DPCPX did not alter this effect (p > 0.05). Moreover, DPCPX significantly reduced the protein expression of the M2 macrophage marker, MRC1. In BMDM, tramadol significantly reduces inflammatory cytokines release, and DPCPX abrogated this effect (p < 0.05). We identify tramadol's peripheral effect is mediated by adenosine A 1 receptor, possibly expressed in macrophages in the TMJ tissue. We also determined an important discovery related to the activation of A 1 R/α2 a receptors in the tramadol action., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Tramadol is a centrally acting synthetic opioid analgesic and SNRI (serotonin/norepinephrine reuptake-inhibitor) that structurally resembles codeine and morphine. Given the tramadol neurotoxic effect and the body of studies on the effect of tramadol on the cerebellum, this study aims to provide deeper insights into molecular and histological alterations in the cerebellar cortex related to tramadol administration. In this study, twenty-four adult male albino rats were randomly and equally divided into two groups: control and tramadol groups. The tramadol group received 50 mg/kg of tramadol daily for 3 weeks via oral gavage. The functional and structural change of the cerebellum under chronic exposure of tramadol were measured. Our data revealed that treating rats with tramadol not only lead to cerebellum atrophy but also resulted in the actuation of microgliosis, neuroinflammatoin, and apoptotic biomarkers. Our results illustrated a significant drop in VEGF (vascular endothelial growth factor) level in the tramadol group. Additionally, tramadol impaired motor coordination and neuromuscular activity. We also identified several signaling cascades chiefly related to neurodegenerative disease and energy metabolism that considerably deregulated in the cerebellum of tramadol-treated rats. Overall, the outcomes of this study suggest that tramadol administration has a neurodegeneration effect on the cerebellar cortex via several pathways consisting of microgliosis, apoptosis, necroptosis, and neuroinflammatoin., (© 2021. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

The use of tramadol is a controversial topic in cycling. In order to provide novel evidence on this issue, we tested 29 participants in a pre-loaded cycling time trial (TT; a 20-min TT preceded by 40-min of constant work-rate at 60% of the VO 2max ) after ingesting 100 mg of tramadol (vs placebo and paracetamol (1.5 g)). Participants performed the Psychomotor Vigilance Task (PVT) at rest and a Sustained Attention to Response Task (SART) during the 60 min of exercise. Oscillatory electroencephalography (EEG) activity was measured throughout the exercise. The results showed higher mean power output during the 20-min TT in the tramadol vs. paracetamol condition, but no reliable difference was reported between tramadol and placebo (nor paracetamol vs. placebo). Tramadol resulted in faster responses in the PVT and higher heart rate during exercise. The main effect of substance was reliable in the SART during the 40-min constant workload (no during the 20-min TT), with slower reaction time, but better accuracy for tramadol and paracetamol than for placebo. This study supports the increased behavioural and neural efficiency at rest for tramadol but not the proposed ergogenic or cognitive (harmful) effect of tramadol (vs. placebo) during self-paced high-intensity cycling.

The objective of this study was to develop a novel acetaminophen and tramadol hydrochloride-loaded soft capsule (ATSC) with enhanced bioavailability of tramadol. The ATSC was manufactured in a pilot-scale batch size with the capsule contents composed of tramadol, acetaminophen, PEG 400 and Capmul MCM at a weight ratio of 37.5:325:177.5:30. Moreover, its dissolution, stability and pharmacokinetics in beagle dogs were carried out compared to commercial tablet. The dissolved amounts of acetaminophen from the ATSC and commercial tablet were not significantly different. However, compared to the latter, the former had significantly higher dissolution rate of tramadol at the initial times. In beagle dogs, the ATSC provided no significant difference in plasma concentrations and AUC of acetaminophen than did the commercial tablet; however, it significantly improved those of tramadol compared to the other, indicating the enhanced oral bioavailability of tramadol. Compared to the commercial tablet, the ATSC had a larger AUC value for tramadol (55.27 ± 11.06 vs. 92.62 ± 21.52 h·ng/ml). In the accelerated long-term stability, the ATSC offered higher than 96% drug content of acetaminophen and tramadol, suggesting that it was stable for at least six months. Therefore, this ATSC would be a recommendable candidate with enhanced oral bioavailability and excellent stability.

The local administration of analgesic combinations by means of degradable polymeric drug delivery systems is an alternative for the management of postoperative pain. We formulated a Tramadol-Dexketoprofen combination (TDC) loaded in poly(vinyl alcohol) (PVA) film. Films were prepared by the solvent casting method using three different molecular weights of PVA and crosslinking those films with citric acid, with the objective of controlling the drug release rate, which was evaluated by UV-vis spectrometry. Non-crosslinked PVA films were also evaluated in the experiments. Differential scanning calorimetry (DSC) analysis of samples corroborated the crosslinking of PVA by the citric acid. Blank and loaded PVA films were tested in vitro for its impact on blood coagulation prothrombin time (PT) and partial thromboplastin time (PTT). The swelling capacity was also evaluated. Crosslinked PVA films of higher-molecular weight showed a prolonged release rate compared with that of the lower-molecular-weight films tested. Non-crosslinked PVA films released 11-14% of TDC. Crosslinked PVA films released 80% of the TDC loaded (p < 0.05). This suggests that crosslinking films can modify the drug release rate. The blank and loaded PVA films induced PT and PTT in the normal range. The results showed that the polymeric films evaluated here have the appropriate properties to allow films to be placed directly on surgical wounds and have the capacity for controlled drug release to promote local analgesia for the control of postoperative pain.

Background: Magnesium ions (Mg 2+ ) increase and prolong opioid analgesia in chronic and acute pain. The nature of this synergistic analgesic interaction has not yet been explained. Our aim was to investigate whether Mg 2+ alter tramadol pharmacokinetics. Our secondary goal was to assess the safety of the combination., Methods: Tramadol was administered to healthy Caucasian subjects with and without Mg 2+ as (1) single 100-mg and (2) multiple 50-mg oral doses. Mg 2+ was administered orally at doses of 150 mg and 75 mg per tramadol dosing in a single- and multiple-dose study, respectively. Both studies were randomized, open label, laboratory-blinded, two-period, two-treatment, crossover trials. The plasma concentrations of tramadol and its active metabolite, O-desmethyltramadol, were measured., Results: A total of 25 and 26 subjects completed the single- and multiple-dose study, respectively. Both primary and secondary pharmacokinetic parameters were similar. The 90% confidence intervals for C max and AUC 0-t geometric mean ratios for tramadol were 91.95-102.40% and 93.22-102.76%. The 90% confidence intervals for C max,ss and AUC 0-τ geometric mean ratios for tramadol were 93.85-103.31% and 99.04-105.27%. The 90% confidence intervals for primary pharmacokinetic parameters were within the acceptance range. ANOVA did not show any statistically significant contribution of the formulation factor (p > 0.05) in either study. Adverse events and clinical safety were similar in the presence and absence of Mg 2+ ., Conclusions: The absence of Mg 2+ interaction with tramadol pharmacokinetics and safety suggests that this combination may be used in the clinical practice for the pharmacotherapy of pain.

Tramadol is used as an analgesic in humans and some animal species. When tramadol is administered to most species it undergoes metabolism to its main metabolites M1 or O-desmethyltramadol, and M2 or N-desmethyltramadol, and many other metabolites. This study describes the pharmacokinetic profile of tramadol when a single subcutaneous bolus of 2 mg/kg was initially administered to two koalas. Based on the results of these two koalas, subsequently 4 mg/kg as a single subcutaneous injection, was administered to an additional four koalas. M1 is recognised as an active metabolite and has greater analgesic activity than tramadol, while M2 is considered inactive. A liquid chromatography assay to quantify tramadol, M1 and M2 in koala plasma was developed and validated. Liquid chromatography-mass spectrometry confirmed that M1 had been identified. Additionally, the metabolite didesmethyltramadol was identified in chromatograms of two of the male koalas. When 4 mg/kg tramadol was administered, the median half-life of tramadol and M1 were 2.89 h and 24.69 h, respectively. The M1 plasma concentration remained well above the minimally effective M1 plasma concentration in humans (approximately 36 ng/mL) over 12 hours. The M1 plasma concentration, when tramadol was administered at 2 mg/kg, did not exceed 36 ng/mL at any time-point. When tramadol was administered at 2 mg/kg and 4 mg/kg the area under the curve M1: tramadol ratios were 0.33 and 0.50, respectively. Tramadol and M1 binding to plasma protein were determined using thawed, frozen koala plasma and the mean binding was 20% and 75%, respectively. It is concluded that when tramadol is administered at 4 mg/kg as a subcutaneous injection to the koala, it is predicted to have some analgesic activity., Competing Interests: The authors have declared that no competing interests exist.

Objectives: The objective of this study was to establish physiologically based pharmacokinetic (PBPK) models of tramadol and its active metabolite O-desmethyltramadol (M1) and to explore the influence of CYP2D6 gene polymorphism on the pharmacokinetics of tramadol and M1. Furthermore, we used PBPK modeling to prospectively predict the extent of drug-drug interactions (DDIs) in the presence of genetic polymorphisms when tramadol was co-administered with the CYP2D6 inhibitors duloxetine and paroxetine., Methods: Plasma concentrations of tramadol and M1 were used to adjust the turnover frequency (K cat ) of CYP2D6 for phenotype populations with different CYP2D6 genotypes. PBPK models were developed to capture the pharmacokinetics between CYP2D6 extensive metabolizers (EMs), intermediate metabolizers (IMs), poor metabolizers (PMs), and ultra-rapid metabolizers (UMs). The validated models were then used to support dose adjustment in different CYP2D6 phenotypes and to predict the extent of CYP2D6-mediated DDIs when tramadol was co-administered with paroxetine or duloxetine., Results: The PBPK models we built accurately describe tramadol and M1 exposure in the population with different CYP2D6 phenotypes. In our prediction, the area under the concentration-time curve (AUC inf-tDlast ) of M1 is 70% lower in PMs than in EMs, 27% lower in IMs, and 15% higher in UMs. Based on the models we built, we suggest that the oral dose of tramadol should be 50% higher for IMs and 25% lower for UMs to achieve an approximately equivalent plasma exposure of M1 as in EMs. When tramadol was co-administered with paroxetine or duloxetine, the magnitude of the inhibitor-substrate interaction was lowest in EMs (0.45), secondary in IMs (0.39), and highest in PMs (0.18) in terms of M1., Conclusion: The current example uses the PBPK model to guide dose adjustment of tramadol and to predict the effect of CYP2D6 genetic polymorphisms on DDIs for rational clinical use of tramadol in the future., (© 2020 Pharmacotherapy Publications, Inc.)

Objectives: Our study will investigate the effect of ultrasound-guided thoracic paravertebral block (UG-TPVB) on postoperative pain, quality of life, and enhanced recovery in patients with non-small-cell lung cancer (NSCLC) undergoing lobectomy surgery., Methods: Our study included 100 patients aged 52 to 75 years who underwent lobectomy surgery with pathological diagnosis of NSCLC. Patients received ultrasound-guided thoracic paravertebral block or general anesthesia with tracheal intubation. Patients' pain score was recorded on a numeric rating scale (NRS) 24 hours post operation. The total postoperative dosage of tramadol hydrochloride, length of hospitalization, quality of life (QoL), and inflammation levels were recorded., Results: Compared with patients who received general anesthesia with tracheal intubation, patients in the UG-TPVB group had lower postoperative NRS scores at 24 h (1.8 vs. 3.5, P = 0.035); the average 24 h postoperative NRS score of the UG-TPVB group is lower than that of the general anesthesia with tracheal intubation (4.6 vs. 5.3, P = 0.012), thus receiving less dosage of tramadol hydrochloride (221 ± 45 vs. 250 ± 38 mg, P < 0.01). Patients in the UG-TPVB group had better EORTC QLQ-C30 scores compared with patients in the general anesthesia with tracheal intubation group. The difference of length of hospitalization, hs-CRP, and IL-6 between two groups did not reach statistical difference (length of hospitalization 6.2 vs. 6.9 days, P = 0.055; hs-CRP: 7.1 ± 1.9 vs. 10.4 ± 6.6, P = 0.095; and IL-6: 71.3 ± 7.2 vs. 68.9 ± 8.7, P = 0.529). Discussion . NSCLC patients undergoing lobectomy surgery who received UG-TPVB had less postoperative pain, used less dosage of tramadol hydrochloride, and had better QoL., Competing Interests: The authors declare that they have no conflicts of interest., (Copyright © 2021 Cuijuan Zheng et al.)

Tramadol, a weak agonist of mu-opioid receptors, causes seizure via several mechanisms. Preconditioning has been purposed to reduce the epileptic seizures in animal models of epilepsy. The preconditioning effect of tramadol on seizure is not studied yet. This study was designed to evaluate the preconditioning effect of ultra-low dose of tramadol on the seizures induced by tramadol at high dose. Furthermore, regarding the critical role of glutamate signaling in the pathogenesis of epilepsy, the effect of preconditioning on some glutamate signaling elements was also examined. Male Wistar rats received tramadol (2 mg/kg, i.p) or normal saline (1 mL/kg, i.p) in preconditioning and control groups, respectively. After 4 days, the challenging tramadol dose (150 mg/kg) was injected to all rats. Epileptic behaviors were recorded during 50 min. The expression of Norbin (as a regulator of metabotropic glutamate receptor 5), Calponin3 (as a regulator of excitatory synaptic markers), NR1 (NMDA receptor subunit 1) and GluR1 (AMPA receptor subunit 1) was measured in hippocampus, prefrontal cortex (PFC) and amygdala. Preconditioning decreased the number and duration of tremors and tonic-clonic seizures. Norbin, Calponin3, NR1 and GluR1 expression were decreased in hippocampus, and preconditioning had no effect on them. In contrast, it increased Norbin expression in PFC and amygdala, and attenuated NR1 and GluR1 upregulation following tramadol at high dose. These findings indicated that preconditioning by ultra-low dose of tramadol protected the animals against seizures following high dose of tramadol mediated, at least in part, by Norbin up regulation, and NR1 and GluR1 down regulation., (Copyright © 2020. Published by Elsevier Masson SAS.)

Background: Tramadol is used off-label for medically supervised opioid withdrawal. Tramadol is metabolized by CYP2D6 to an active metabolite with significantly more pharmacologic activity compared to the parent compound. Objectives: The objective of this study is to evaluate the effects of CYP2D6 inhibitors on patient response to a tramadol taper for medically supervised opioid withdrawal. Methods: A retrospective chart review of patients who received a tramadol taper for medically supervised opioid withdrawal was conducted comparing patients who received concomitant moderate-to-strong CYP2D6 inhibitors to patients without concomitant therapy. The primary outcome was the change in Clinical Institute Narcotic Assessment (CINA) scores from baseline to discharge. Secondary outcomes included area under the curve of CINA scores over time, additional CINA outcomes, length of stay, and readmissions. Results: Of 100 charts reviewed, 30 patients received a concomitant moderate-to-strong CYP2D6 inhibitor. There were no statistically significant differences between the baseline demographics of the two groups. Change from baseline CINA to discharge did not differ significantly between the Non-2D6 group and the 2D6 group (-4.0 ± 3.83 and -4.5 ± 4.48 respectively; p = 0.606). The average CINA score for nausea and vomiting was significantly higher in the Non-2D6 group compared to the 2D6 group (0.34 ± 0.35 and 0.18 ± 0.33 respectively; p = 0.019). Otherwise there were no significant differences found in any secondary outcomes. Conclusions: Based on these results, moderate-to-strong CYP2D6 inhibitors do not appear to have a significant impact on the withdrawal course for patients treated with a high-dose tramadol taper.

Introduction: Women experience pain during medical abortion, yet optimal pain management remains unclear. We studied the pain experience and need of analgesics during early medical abortion (≤63 days of gestation) among teenage and adult women. We also assessed predictive factors of severe pain., Material and Methods: We recruited 140 primigravid women: 60 teenagers and 80 adult women aged between 25 and 35 years old. The group of teenagers included 19 women under the age of 18 years old (minors). The abortion was performed with mifepristone (200 mg) followed by vaginal misoprostol (800 μg), mainly self-administered at home for adults. Minors were hospitalized during misoprostol administration. Pain medication consisted of ibuprofen 600 mg and paracetamol 1000 mg, first doses taken simultaneously with misoprostol and repeated, if needed, up to three times daily. Additional opiates (mainly tramadol or oxycodone) were administered at hospital if needed. Pain was measured using the visual analogue scale (VAS, 0-100 mm)., Results: The maximal pain VAS (median, interquartile range) was 75 (54-91). Of all the women, 57.7% experienced severe pain (VAS ≥70) during abortion care and 93.5% of women needed additional analgesics in addition to prophylactic pain medication. Teenagers needed additional analgesics more often than adults (5 [3-8] vs 3 [2-6] times, P = .021); 38.0% of all teenagers (64.7% of the minors) received additional opiates compared with 7.9% in adult women. Severe pain (VAS ≥70) was associated with history of dysmenorrhea (adjusted odds ratio [OR] 2.60 [95% confidence interval [CI] 1.21-5.59, P = .014]), anxiety at baseline (2.64 [1.03-6.77], P = .044) and emesis during abortion (5.24 [2.38-11.57], P < .001). Hospital administration of misoprostol did not lower the risk for severe pain experience (OR 0.84 [95% CI 0.34-2.05], P = .694). Satisfaction with care was high in study population (median VAS 91 [interquartile range 79-97]) and was not associated with the use of narcotic analgesic or place of misoprostol administration., Conclusions: Pain intensity was high both in teenage and adult women undergoing medical abortion, yet satisfaction on care was high. More effective analgesics than ibuprofen and paracetamol should be offered to all women undergoing early medical abortion, especially to those with history of dysmenorrhea. Also, routine use of antiemetics might be advisable., (© 2020 The Authors. Acta Obstetricia et Gynecologica Scandinavica published by John Wiley & Sons Ltd on behalf of Nordic Federation of Societies of Obstetrics and Gynecology (NFOG).)

The purpose of this study was to investigate the effect of tramadol (TM) (2 mg/kg) administered intramuscularly (IM) followed by a constant rate infusion (CRI) of TM (2 mg/kg/h) in pigs. Sixteen pigs undergoing experimental surgery were premedicated IM with a combination of alfaxalone (5 mg/kg) and midazolam (0.5 mg/kg). Anaesthesia was induced with propofol (2 mg/kg) intravenously (IV) and maintained with isoflurane. Pigs were randomly assigned to one of the two following groups: Group 1 (n=8): received a loading dose of TM (2 mg/kg) followed by a CRI of TM (2 mg/kg/h); Group 2 (n=8): a loading dose of TM (2 mg/kg) followed by a CRI of lactated Ringer's solution (2 ml/kg/h). Heart rate (HR), respiratory rate (RR), rectal temperature (RT), haemoglobin oxygen saturation (SpO2), fraction of inspired oxygen (FIO2), end-tidal concentration of isoflurane (FEISO), end-tidal carbon dioxide concentration (FECO2), pH, arterial oxygen partial pressure (PaO2), arterial carbon dioxide partial pressure (PaCO2) and bicarbonate concentration (HCO3-) were recorded immediately after loss of righting reflex (T=0 min) and at 15-min intervals over a period of 60 min. Continuous data were analysed using a repeated- -measure analysis of variance (ANOVA) and a p-value ⟨0.05 was considered significant. HR, RR and FEISO were significantly lower (p⟨0.05) in Group 1 at T30 and T45, which corresponded to the time of the most intense surgical stimulation. The results suggest that the TM infusion minimizes the HR and RR response, slightly reducing isoflurane requirements and determining a superior perioperative analgesia., (Copyright© by the Polish Academy of Sciences.)

This controlled study aimed to measure concentrations of tramadol (TRA) and its two main metabolites, N-desmethyltramadol (NDMT) and O-desmethyltramadol (ODMT), in hair following a single dose ingestion and to investigate the distribution patterns in hair by segmental analysis of hair samples taken at several sampling time points after ingestion. An oral dose (50 or 100mg) of TRA was administered to 17 healthy volunteers. Hair samples were collected prior to drug administration and 14, 30, 60 and 120 days after ingestion. Each sample was segmented in 5mm segments and washed. The analytes were extracted from pulverized hair by incubation in extraction media for 18h at 37°C. A validated UHPLC-MS/MS method was used to quantify the analytes at a LLOQ of 0.001ng/mg. Hair segments corresponding to the time of ingestion were positive for TRA and the metabolites of each sampling time point, although neighboring segments also showed positive results. The highest concentrations for both dosage groups were observed in the proximal segment of hair collected 14 days after ingestion for all subjects: 0.061-0.95ng TRA/mg, 0.012-0.86ng NDMT/mg and 0.009-0.17ng ODMT/mg (n=16). Generally, the TRA concentration was higher than the metabolites concentrations but depended on the CYP2D6 phenotype. The metabolite to TRA ratios were stable within a subject over the sampling time points, however it varied greatly between subjects. No significant differences in hair concentrations were found between the two dosage groups at each sampling time. Several confounding factors were identified such as hair pigmentation and internal sweat. We showed that analysis of 5mm segments improved the determination of the exposure time after a single ingestion of TRA. In addition, in the later sampling time points the analytes were spread more between segments and the total drug amount of each later sampling time point declined up to a 100% (median: 75%) due to wash out. The presented results are important additions to the sparse literature reporting single dose of psychoactive drugs in hair., Competing Interests: Declaration of Competing Interest The authors report no declarations of interest., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Aims: Previous investigations demonstrated that tramadol, as a painkiller, similar to morphine induces tolerance and dependence. Furthermore, the cannabinoid receptor 1 (CB1R) located in the nucleus accumbens (NAc) plays a critical role in morphine-induced conditioning. Therefore, the main objective of this study was to evaluate the role of NAc CB1R in tramadol induced conditioning and reinstatement., Main Methods: In the present experiment, the effect of NAc CB1 receptors on tramadol induced conditioning was tested by microinjecting of arachidonylcyclopropylamide (ACPA, CB1R agonist) and AM 251 (CB1R inverse agonist) in the NAc during tramadol-induced conditioning in the adult male Wistar rats. In addition, the role of NAc CB1R in the reinstatement was also evaluated by injecting ACPA and AM 251 after a 10-days extinction period., Key Findings: The obtained data revealed that the administration of tramadol (1,2, and 4 mg/kg, ip) dose-dependently produced conditioned place preference (CPP). Moreover, intra-NAc administration of ACPA (0.25, 0.5, and 1 μg/rat) dose-dependently induced conditioning, while the administration of AM-251 (30, 60, and 120 ng/rat) induced a significant aversion. In addition, the administration of a non-effective dose of AM251 during tramadol conditioning inhibited conditioning induced by tramadol. On the other hand, the administration of ACPA after extinction induced a significant reinstatement. Notably, the locomotor activity did not change among groups., Significance: Previous studies have shown that tramadol-induced CPP occurs through μ-opioid receptors. The data obtained in the current study indicated that CB1R located in the NAc is involved in mediating conditioning induced by tramadol. Besides, CB1R also plays a vital role in the reinstatement of tramadol-conditioned animals. It might be due to the effect of opioids on enhancing the level of CB1R., (Copyright © 2020. Published by Elsevier Inc.)

Purpose: This study aimed to investigate seizures and anxiety-like behaviors in immature rats prenatally exposed to opiate drugs. Materials and methods: Pregnant rats were randomly divided into five groups: saline, morphine, tramadol, methadone, and buprenorphine. Administrations were performed intraperitoneally once a day for the last seven days of pregnancy. Neonatal rats were subdivided into ten groups, split according to sex. Anxiety-like behavior was tested on postnatal day (PD) 19. On PD 20, seizure was induced by PTZ injection. Results: Morphine in male rats had an increased time to onset ( p  < 0.005), whereas there was a decreased number of tonic-clonic seizures in females ( p  < 0.05). Tramadol had an increased duration of tonic-clonic seizures compared to morphine and methadone in males ( p Moreover, tramadol decreased open arm time and locomotor activity in males more than in females ( ). Moreover, tramadol decreased open arm time and locomotor activity in males more than in females ( p  < 0.05). Furthermore, buprenorphine and tramadol decreased open arm entrance in male rats ( p  < 0.05). Furthermore, buprenorphine and tramadol decreased open arm entrance in male rats ( p It was demonstrated that prenatal tramadol significantly increases both the duration of seizures and anxiety-like behaviors in immature male rats, whereas morphine decreases both of them. The effects of tramadol on seizure and anxiety-like behavior may be due to the comorbid occurrence of the symptoms of these two disorders.Conclusions: It was demonstrated that prenatal tramadol significantly increases both the duration of seizures and anxiety-like behaviors in immature male rats, whereas morphine decreases both of them. The effects of tramadol on seizure and anxiety-like behavior may be due to the comorbid occurrence of the symptoms of these two disorders.

Background and Objective: Oral tramadol, an atypical opioid approved in the United States (US) since 1995 and a Schedule IV controlled substance, has less abuse liability compared to Schedule II conventional opioids. Intravenous (IV) tramadol is not available in the US, but has the potential to fill a gap between non-opioid medications and conventional opioids for treatment of acute pain. This study evaluates IV tramadol in the management of postoperative pain compared to placebo and standard-of-care active control., Methods: A phase 3, multicenter, double-blind, three-arm, randomized, placebo- and active-controlled, multiple-dose, parallel-group study was conducted to evaluate the efficacy and safety of 50 mg IV tramadol versus placebo and 4 mg IV morphine over 48 h in patients with postoperative pain following abdominoplasty surgery., Results: IV tramadol was statistically superior (p < 0.05) to placebo and comparable to IV morphine for the primary and all key secondary efficacy outcomes and demonstrated numerically lower rates for the incidence of most common treatment-emergent adverse events (TEAEs) compared to morphine. No unexpected findings were observed for TEAEs, laboratory tests, vital signs, or electrocardiograms (ECGs). Over 90% of patients completed the study., Conclusion: The study demonstrated that IV tramadol 50 mg is highly effective in the management of postoperative pain following abdominoplasty. The consistency of effects between tramadol and morphine (as compared to placebo) for primary and key secondary endpoints validates the efficacy of tramadol observed. The study also provided direct evidence of improved tolerability of IV tramadol over a standard-of-care conventional Schedule II opioid. IV tramadol may become a useful option in patients where exposure to conventional opioids is not desired.

Background: Postoperative pain in ambulatory surgery is a multifactorial issue affecting patient satisfaction, time of discharge, and rehospitalization. This study evaluated the efficacy and safety of nalbuphine for the treatment of postoperative pain after ambulatory surgery, relative to tramadol., Methods: This multi-center, randomized, double blind, and controlled study was conducted at 10 centers. In accordance with the inclusion criteria, 492 ambulatory surgery patients were recruited. These patients had moderate to severe pain after ambulatory surgery, with a visual analogue scale (VAS) score > 3 cm. They were randomly divided into an experimental (n = 248) or control (n = 244) group and treated for analgesia with 0.2 mg/kg of nalbuphine or 2 mg/kg of tramadol, respectively. VAS scores, adverse events, and vital signs of the patients were recorded before administration (baseline; T 1 ); and 30 min (T 2 ), 2 h (T 3 ), 4 h (T 4 ), and 6 h (T 5 ) after administration of analgesia. A decrease in pain intensity of more than 25% compared with the baseline was used as an indicator of analgesic efficacy. The experimental and control groups were compared with regard to this indicator of efficacy at each timepoint., Results: The VAS scores of the experimental and control groups were statistically comparable at timepoints T 1 -T 4 . At T 5 , the VAS scores of the experimental group were significantly lower than that of the control. The pain intensity was significantly higher in the experimental group compared with the control at T 2 and T 3 . Adverse events and vital signs were similar for the two groups at each timepoint., Conclusions: Nalbuphine can provide effective and safe pain relief in patients after ambulatory surgery., Trial Registration: The registration number is ChiCTR-IOR-16010032 , the date of registration was 2016-11-28.

Background: In the practice of postoperative pain management, pain is still poorly managed in low resource setting where the practice of epidural and opioid free analgesia is impractical. There has been a recent trend of combining different drugs and concept of preemptive analgesia but the therapeutic superiority remains understudied for postoperative pain management. The aim of this study is to assess postoperative analgesic effect of preemptive Paracetamol, Paracetamol-diclofenac and Paracetamol-tramadol combination in patients undergoing laparotomy surgery., Methods: Three-arm, randomized control trial study conducted on 63 patients undergone laparotomy surgery; group-P (paracetamol 1 g), group-PD (1 g + diclofenac 75 mg) and group-PT (paracetamol 1 g + tramadol 100 mg). The Numerical Rating Scale (NRS) pain rating system was used for this study. The primary endpoint of the study was total amount of analgesia consumption. Post-operative analgesic therapy [intravenous tramadol, 50 mg] were provided when patients complain of pain (request medication) or a numeric rating scale ≥4 was recorded. Secondary endpoint of the study were the time of first analgesic request and the intensity of the pain during 24 h post-op follow up period. Parametric data were analyzed using (ANOVA) and nonparametric data analyzed by Kuruska-Wallis H rank test. Chi-square test used for categorical variable. Statistical significance were sated at p value < 0.05 with a power of 80%., Results: The mean total tramadol consumption was significant higher in paracetamol group 250 ± 79.06 mg compared to paracetamol-diclofenac (173.81 ± 87.49 mg p = 0. 008) and paracetamol-tramadol (154.76 ± 70.54 mg p = 0. 001) group. Time to first analgesic request was significantly shorter within paracetamol group (87.62 ± 20.95 min) compared to paracetamol-diclofenac (103.01 ± 23.53 min p = 0.029) and paracetamol-tramadol (144.05 ± 14.72 min p < 0.001) group. There was statistically significant difference at 4th, 6th and 8th hour showing lower median pain score in paracetamol-tramadol group compared to paracetamol group., Conclusion: Preemptive combination of paracetamol-tramadol and paracetamol-diclofenac reduce total tramadol consumption and prolongs time to first analgesic request compared to paracetamol alone in patients undergoing laparotomy surgery., Trial Registration: The study was retrospectively registered on 07 July 2019 at Pan African Clinical Trial Registry with the identification number of PACTR201908890749145 . It was accepted on 14 August 2019.