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Nonsteroidal anti-inflammatory drugs (NSAIDs) inhibit the enzyme cyclooxygenase (COX), which forms prostaglandins involved in pain and inflammation. COX inhibitors have analgesic and anti-inflammatory effects, but also increase risks for gastrointestinal ulcers, bleeding, and renal and cardiovascular adverse events. Identification of two isoforms of COX, COX-1 and COX-2, led to the development of selective COX-2 inhibitors, which were launched as having fewer gastrointestinal side effects since gastroprotective prostaglandins produced via COX-1 are spared. The balance between COX-1 mediated prothrombotic thromboxane and COX-2 mediated antithrombotic prostacyclin is important for thrombotic risk. An increased risk of suffering myocardial infarction and death with COX-2 inhibitor treatment is well established from clinical trials and observational research. Rofecoxib (Vioxx) was withdrawn from the market for this reason, but the equally COX-2 selective etoricoxib has replaced it in Europe but not in the United States. The "traditional" NSAID diclofenac is as COX-2 selective as celecoxib and increases cardiovascular risk dose dependently. COX inhibitor dosages should be lower in osteoarthritis than in rheumatoid arthritis. Randomized trials comparing COX-2 inhibitors with NSAIDs have exaggerated their gastrointestinal benefits by using maximal NSAID doses regardless of indication, and/or hidden the cardiovascular risk by comparing with COX-2 selective diclofenac instead of low-dose ibuprofen or naproxen. Observational studies show increased cardiovascular risks within weeks of treatment with COX-2 inhibitors and high doses of NSAIDs other than naproxen, which is the safest alternative. COX inhibitors are symptomatic drugs that should be used intermittently at the lowest effective dosage, especially among individuals with an increased cardiovascular risk.

Background Local infiltration analgesia (LIA) with local anaesthetic (ropivacaine), a nonsteroidal anti-inflammatory drug (ketorolac) and epinephrine after lower extremity arthroplasty has gained increasing popularity during the last decade. This method has certain advantages, which include minimal systemic side effects, faster post-operative mobilization, earlier post-operative discharge from hospital and less opioid consumption. However, information regarding plasma concentrations of ketorolac after LIA mixture is insufficient to predict the risk of renal impairment in patients subjected to arthroplasty. Aim To determine the maximal plasma concentration and the exposure of ketorolac during the first 30 h following LIA in hip arthroplasty. Methods Thirteen patients scheduled for primary total hip arthroplasty with LIA (ropivacaine 200 mg, ketorolac 30 mg and epinephrine 0.5 mg in a volume of 106 ml) were included. Plasma concentration of ketorolac was quantified by liquid chromatography-mass spectrometry. In addition, we assessed the effect of increasing age and decreasing glomerular filtration rate on the maximal plasma concentration and the total exposure to ketorolac during 30 h. Results The range of the maximal plasma concentration, 0.3–2.2 mg/l, was detected 30 min–4 h after completing the infiltration. Similar plasma levels have been reported after intramuscular injection of the same dose of ketorolac to healthy elderly volunteers. Conclusion Exposure to ketorolac after LIA may be comparable to an intramuscular injection of the same dose. Decision of dose reduction should be based on clinical assessment of risk factors.

Background Ketobemidone is often used as an alternative to morphine in children in the Scandinavian countries. In an earlier study, we have examined the pharmacokinetic properties in children in different age groups but have not focused on neonates. The aim of this clinical trial was to explore the pharmacokinetics of ketobemidone in neonates. Methods Fifteen full-term neonates (eight females) from 37 gestational weeks at birth and scheduled for elective surgery were included in the trial. Their median age was 3 days (range 1–18 days). Ketobemidone hydrochloride was administered as a single intravenous bolus dose, and ketobemidone concentrations were measured by liquid chromatography-mass spectrometry over 10 h. Pharmacokinetic parameters were calculated with standard compartmental methods. Results The median (range) values for ketobemidone clearance, apparent volume of distribution, volume of central compartment, distribution half-life and elimination half-life were 0.46 (0.23–0.84) l/h/kg, 4.64 (3.50–7.31) l/kg, 1.71 (0.16–3.47) l/kg, 2.85 (1.04–10.78) min and 7.26 (3.5–11.3) h. Conclusion Compared with our previous study in children older than 1 year of age, the elimination of ketobemidone appeared to be slower in full-term neonates. Despite a low pharmacokinetic variability of ketobemidone as observed in the present neonatal patient population, we recommend individualizing the dose of ketobemidone based on observations of analgesic efficacy.

IntroductionChronic pain and the pattern of opioid use after skeletal fractures has been a neglected topic in pain medicine. Pelvic and in particular acetabular fractures represent some of the most troublesome injuries for patients with a high incidence of chronic pain after fracture. We examined the long-term opioid analgesic use among patients with acetabular fractures and analysed if potential risk factors would predict a prolonged opioid therapy.Patients and methodsData were extracted from medical databases such as the Swedish National Hospital Discharge Register and the National Pharmacy Register. The study period was 2005–2008. Kaplan–Meier analysis constructed the cumulative opioid consumption with 95% confidence intervals (CI). Cox multiple-regression model was used to study risk factors for a prolonged opioid prescription after admission for fracture. An age- and sex-matched control group was included for comparisons.ResultsWe identified 1017 patients with isolated acetabular fractures. The proportion of dispensing opioids for these patients was 39%, which was 7 times higher than in the age- and sex-matched non-fracture controls (n=5077). The median follow-up time was 14 (interquartile range [IQR] 5–24) months. Most patients with opioid use after fracture were male (60%) and the median age was 76 (IQR 61–85) years. The leading mechanism of injury was fall on the same level (52%). At 6 and 12 months after fracture, 41% (95% CI 36–47) and 33% (28–39) were still treated with opioids. The multiple Cox regression-analysis (adjusted for age, sex, type of treatment, and mechanism of injury) revealed that younger patients (age

The aim was to present and evaluate the impact of a comprehensive strategy over 10 years to select, communicate and achieve adherence to essential drug recommendations (EDR) in ambulatory care in a metropolitan healthcare region. EDRs were issued and launched as a 'Wise List' by the regional Drug and Therapeutics Committee in Stockholm. This study presents the concept by: (i) documenting the process for selecting, communicating and monitoring the impact of the 'Wise List'; (ii) analysing the variation in the number of drug substances recommended between 2000 and 2010; (iii) assessing the attitudes to the 'Wise List' among prescribers and the public; (iv) evaluating the adherence to recommendations between 2003 and 2009. The 'Wise List' consistently contained 200 drug substances for treating common diseases. The drugs were selected based on their efficacy, safety, suitability and cost-effectiveness. The 'Wise List' was known among one-third of a surveyed sample of the public in 2002 after initial marketing campaigns. All surveyed prescribers knew about the concept and 81% found the recommendations trustworthy in 2005. Adherence to recommendations increased from 69% in 1999 to 77% in 2009. In primary care, adherence increased from 83% to 87% from 2003 to 2009. The coefficient of variation (CV%) decreased from 6.1% to 3.8% for 156 healthcare centres between these years. The acceptance of the 'Wise List' in terms of trust among physicians and among the public and increased adherence may be explained by clear criteria for drug recommendations, a comprehensive communication strategy, electronic access to recommendations, continuous medical education and involvement of professional networks and patients.

Background Exposure to Benzodiazepines (BZD) during foetal life has been suggested to contribute to neonatal morbidity and some congenital malformations, for example, orofacial clefts. Here we aimed to study the neonatal outcome and congenital malformations in neonates whose mothers reported use of BZD and/or hypnotic benzodiazepine receptor agonists (HBRA) during pregnancy. Methods In the Swedish Medical Birth Register we identified 1979 infants whose mothers (n = 1944) reported use of BZD and/or HBRA in early pregnancy. An additional 401 infants were studied, born to 390 mothers who were prescribed such drugs during late pregnancy. Neonatal outcome including congenital malformations after exposure was compared with that of all births (n = 873 879). Results An increased risk for preterm birth and low birth weight was detected in the exposed population. The rate of relatively major congenital malformations was moderately increased among infants exposed in early pregnancy (adjusted OR = 1.24, 95%CI 1.00-1.55), not explained by known teratogenic maternal co-medication. A higher than expected number of infants with pylorostenosis or alimentary tract atresia (especially small gut) was found. This was, however, based on only seven infants for each group of malformation without association to any specific BZD or HBRA. The earlier proposed increased risk for orofacial clefts was not confirmed in our study. Conclusions Maternal use of BZD and/or HBRA may increase the risk for preterm birth and low birth weight and cause neonatal symptoms, but does not appear to have a strong teratogenic potential. The tentative association with pylorostenosis and alimentary tract atresia needs confirmation. Copyright (C) 2007 John Wiley & Sons, Ltd. (Less)

Numerous in vitro studies suggest that inflammation is associated with enhanced release of substance P (SP) in the dorsal horn. To test the hypothesis that inflammation increases the evoked concentration of SP in the intact animal, we used in vivo microdialysis with a highly sensitive radioimmunoassay to monitor SP-like immunoreactivity (SP-LI) in the dorsal horn. Seven days after the induction of persistent unilateral inflammation with hindpaw injection of complete Freund's adjuvant, perfusion of the microdialysis probe with 10 microM capsaicin (a concentration which failed to induce SP-LI release in rats without inflammation) induced a significant increase of microdialysate SP-LI. Inclusion of an NMDA antagonist in the perfusion fluid completely blocked this capsaicin-evoked SP release. Administration of a five-fold higher dose of capsaicin did not further increase SP release. These results in a rat model of chronic arthritis suggest that persistent inflammatory signaling facilitates capsaicin-evoked SP release in the dorsal horn in vivo.

Morphine and other opioid agonists induce spinal in vivo release of cholecystokinin (CCK), a neuropeptide with anti-opioid properties. However, so far the opioid receptor subtype responsible for this effect has not been determined. In the present in vivo microdialysis study, the morphine-induced release of cholecystokinin-like immunoreactivity (CCK-LI) in the dorsal horn was completely blocked by the δ-opioid antagonist naltrindole (10 µm in the perfusion fluid). Neither the µ-opioid receptor antagonist d-Phe-Cys-Tyr-d-Trp-Orn-Thr-Pen-Thr amide (CTOP; 10 µm in the perfusion fluid), nor the κ-opioid receptor antagonist nor-binaltorphimine (nor-BNI); 10 µm in the perfusion fluid) had any significant effect in this respect. In addition, systemic administration of the δ-opioid receptor agonist BW373U86 (1 mg/kg, s.c.) and spinal administration of the δ2-opioid receptor agonist, Tyr-d-Ala-Phe-Glu-Val-Val-Gly amide ([d-Ala2] deltorphin II) (1 µm in the perfusion fluid) induced a significant increase of the CCK-LI level. The effect of BW373U86 on spinal CCK-LI release was completely blocked by spinal administration of naltrindole. The µ-opioid receptor agonist [D-ala2-N-Me-Phe4-Gly5-ol]-enkephalin (DAMGO) (1 µm in the perfusion fluid or 1 mg/kg, s.c.) failed to alter the CCK-LI level. Peripheral nerve lesions have previously been shown to down-regulate µ- and δ-opioid receptors in the dorsal horn, to increase the gene-expression of CCK and CCK-receptor mRNA in dorsal root ganglion neurons and to alter the potassium-induced spinal CCK-LI release. After complete sciatic nerve transection, administration of the two selective δ-opioid receptor agonists induced a significant release of CCK-LI, which was comparable to controls. In contrast, neither systemic nor spinal administration of morphine and DAMGO altered the spinal CCK-LI release in axotomized animals. The present data indicate that the δ-opioid receptor mediates morphine-induced CCK-LI release in the spinal cord.

The gene expression of cholecystokinin (CCK), a neuropeptide with anti-opioid properties, has been reported to be up-regulated in some primary sensory neurons after a peripheral nerve lesion. We have recently demonstrated that the up-regulation of CCK mRNA is not accompanied by an increased potassium-evoked release of CCK-like immunoreactivity (CCK-LI) 2-4 weeks after a complete transection of the sciatic nerve. The potassium-evoked release of CCK-LI at earlier and later time points has, however, not been studied. The aim of the present in vivo microdialysis study was to monitor how the basal and stimulated extracellular level of CCK in the dorsal horn of the spinal cord is affected at various time points after a complete transection of the sciatic nerve (axotomy). During the first week after transection of the sciatic nerve a tendency towards an elevation of the potassium-induced (100 mM in the perfusion fluid) release of spinal CCK-LI was observed. In contrast, no potassium-induced release of CCK-LI could be detected 2-3 weeks and 2 months after axotomy. No significant effect was observed on the basal extracellular levels of CCK-LI in the dorsal horn. The present study provides further support for the notion that the adaptive changes in the dorsal horn 2 weeks and later after a deafferentiation injury do not include an increased release of CCK.

The anterior cingulate cortex (ACC) is a limbic region with a high density of cholecystokinin (CCK) immunoreactivity, that has been suggested to be of importance for the affective and emotional component of pain. In the present microdialysis study, performed in the awake rat, we demonstrate a bilateral 4- to 6-fold increase of the potassium-induced release of CCK-like immunoreactivity (CCK-LI) in the ACC 2-3 weeks after a unilateral transection of the sciatic nerve (axotomy), an animal model of phantom limb or deafferentiation pain. Considering the implication of CCK in pain modulation and anxiety, we suggest that an altered activity of CCK containing neurons in the ACC may be of importance for the affective component of certain pain conditions.

OBJECTIVE The aim of the present study is to monitor the extracellular gamma-aminobutyric acid (GABA) levels in the lumbar dorsal horn of allodynic rats, which respond to spinal cord stimulation (SCS) with a normalization of the tactile withdrawal threshold. In addition, we monitored the GABA levels in nonresponding and sham-stimulated rats. METHODS Partial constriction injury of the sciatic nerve was performed, and a permanent electrode for SCS was inserted into the spinal canal. The response to SCS was assessed with von Frey hairs in awake animals. Later, microdialysis was performed in the dorsal horn of the spinal cord under halothane anesthesia. The concentration of GABA in the microdialysate was assessed by high-performance liquid chromatography. RESULTS Extracellular GABA levels in rats with sciatic nerve lesions and allodynia (2.3 +/- 0.5 nmol/L) were significantly lower (P < 0.001) than in control rats with intact sciatic nerves (8.1 +/- 1.0 nmol/L), whereas only slightly decreased GABA levels (5.7 +/- 1.1 nmol/L) were detected in nonallodynic rats with sciatic nerve lesions. In the allodynic rats, which respond to SCS by a normalization of the tactile withdrawal threshold, significantly (P < 0.001) increased GABA levels (6.7 +/- 2.3 nmol/L) were detected after SCS. In contrast, neither the allodynic rats, which did not respond to SCS, nor the sham-stimulated allodynic rats displayed increased GABA levels in response to stimulation. CONCLUSION Our results indicate that the development of allodynia, a common symptom in neuropathic pain states, may be linked to a decreased spinal release of GABA. We suggest that an SCS-induced release of GABA could be important for the suppression of allodynia observed in rats after SCS. Similar mechanisms could also be involved in the SCS-induced alleviation of pain in patients with peripheral neuropathy.

The mechanism underlying the beneficial effect of electrical stimulation of the posterior surface of the spinal cord in chronic pain states are unknown. The prolonged pain relief following a short stimulation period is believed to imply the activation of long-lasting neurochemical processes, mainly in the spinal cord, but possibly also involving other parts of the central nervous system. Previous studies have demonstrated that substance P and serotonin are released in the cat dorsal horn during spinal cord stimulation (SCS) with electrical parameters similar to those used in the clinic. However, gamma-aminobutyric acid (GABA) has also been hypothesized to play a role in the effect of SCS, but there have been no studies of the possible effects of SCS on GABA release. The authors applied SCS to anesthetized rats and monitored the extracellular concentration of GABA in the lumbar dorsal horns by microdialysis and a sensitive reverse-phase high-performance liquid chromatography technique. After 30 minutes of SCS, the GABA level increased significantly (by almost 270%) in comparison with the basal level recorded before stimulation, from 3.6 +/- 1.0 nmol/L to 13.1 +/- 2.2 nmol/L (mean +/- the standard error of the mean; P < 0.05). The peak release was delayed and appeared in the 30-minute fraction collected after stimulation. Also, perfusion of the dialysis probes with potassium (100 mmol/L) induced an increase of the GABA level. In control experiments without electrical stimulation, slowly decreasing GABA levels were observed throughout the experiments. The present results may suggest an involvement of GABA in the mechanism of SCS-induced pain relief.(ABSTRACT TRUNCATED AT 250 WORDS)

Stimulation of spinal serotonin (5-HT) 2A/2C receptors has previously been reported to lead to either a pro-nociceptive or an anti-nociceptive response. Behavioral data have indicated that the pro-nociceptive effect is related to the release of substance P (SP). The aim of this in vivo microdialysis study was to investigate if stimulation of spinal 5-HT 2A/2C receptors by the selective agonist (±)-2,5-dimethoxy-4-iodoamphetamine (DOI) induces spontaneous or capsaicin-evoked increase in the release of SP-like immunoreactivity (SP-LI) in the rat dorsal horn. A dose of capsaicin (25 μM in the perfusion medium administered for 30 min), which did not lead to a significant release of SP-LI on its own, induced a significant increase of greater than 4-fold of the SP-LI level following spinal application of 50 nmol DOI. Higher (500 nmol) or lower (5 nmol) doses of DOI failed to induce a similar effect. In rats with a peripheral inflammation, induced by carrageenan, capsaicin (25 μM) induced a non-significant increase of SP-LI. A significant 8-fold increase of the SP-LI level was detected following administration of 50 nmol DOI in combination with capsaicin. The effect of DOI, which was completely prevented by co-administration of the 5-HT 2A receptor antagonist ketanserin in control animals without peripheral inflammation, was only partly blocked in animals with carrageenan induced peripheral inflammation. In conclusion, stimulation of 5-HT 2A/2C receptors facilitates the capsaicin-evoked release of SP-LI in the dorsal horn in both animals with and without carrageenan-induced unilateral inflammation. The observation that the highest dose of DOI failed to induce SP-LI release may be due to an inhibitory postsynaptic action at this dose.

The mechanism underlying the beneficial effect of electrical stimulation of the posterior surface of the spinal cord in chronic pain states are unknown. The prolonged pain relief following a short stimulation period is believed to imply the activation of long-lasting neurochemical processes, mainly in the spinal cord, but possibly also involving other parts of the central nervous system. Previous studies have demonstrated that substance P and serotonin are released in the cat dorsal horn during spinal cord stimulation (SCS) with electrical parameters similar to those used in the clinic. However, gamma-aminobutyric acid (GABA) has also been hypothesized to play a role in the effect of SCS, but there have been no studies of the possible effects of SCS on GABA release. The authors applied SCS to anesthetized rats and monitored the extracellular concentration of GABA in the lumbar dorsal horns by microdialysis and a sensitive reverse-phase high-performance liquid chromatography technique. After 30 minutes of SCS, the GABA level increased significantly (by almost 270%) in comparison with the basal level recorded before stimulation, from 3.6 +/- 1.0 nmol/L to 13.1 +/- 2.2 nmol/L (mean +/- the standard error of the mean; P0.05). The peak release was delayed and appeared in the 30-minute fraction collected after stimulation. Also, perfusion of the dialysis probes with potassium (100 mmol/L) induced an increase of the GABA level. In control experiments without electrical stimulation, slowly decreasing GABA levels were observed throughout the experiments. The present results may suggest an involvement of GABA in the mechanism of SCS-induced pain relief.(ABSTRACT TRUNCATED AT 250 WORDS)