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The first-generation antihistamine chlorpheniramine (CPA) is believed to have both anxiolytic and antidepressant properties. The current study sought to assess the mechanisms behind the antidepressant and anxiolytic effects of CPA therapy concerning oxidative stress, inflammation, and nuclear factor p45 for erythroid 2-Brain-derived neurotrophic factor (Nrf2-BDNF) signaling pathway in forced swimming-induced depressive-like behavior and anxiety. Eighteen male Wistar rats (180–200 gm) rats were separated into three groups (n = 6): a stressed group (acute stress) that underwent the forced swimming test (FST) and a stressed group that received pretreatment with CPA (10 mg/kg body weight) for 3 weeks (CPA + acute stress). Animals were subsequently put through the following behavioral tests after undergoing a forced swim test (FST) for 5 min: an immobility test, open field test, and elevated plus maze test. Serum cortisol levels were measured when the rats were euthanized at the end of the experiments. Brain neurotransmitters (cortisol, serotonin, and noradrenaline), oxidative stress (SOD and MDA), inflammatory (IL-6 and IL-1) biomarkers, and the Nrf2-BDNF signaling pathway in the hippocampus and cerebral cortex tissues was determined. CPA prevented stress-induced increases in cortisol levels (p < 0.0001), decreased brain neurotransmitters, and increased oxidative stress and inflammation. CPA also upregulated the Nrf2-BDNF signaling pathway. Thus, CPA mitigates depressive-like behavior and anxiety by inhibiting oxidative stress and inflammation and upregulating the Nrf2-BDNF signaling pathway in the brain tissues.

Objectives: There have been few studies of pharmacobezoar formation, but they can be an important contributor to overdose toxicity. Pharmacobezoars may explain the delayed peak or "double hump" pharmacokinetics, which were noted in previous case reports with delayed toxicity of acetaminophen (APAP). We validated the presence of APAP bezoar formation in a controlled modified in vitro environment simulating acute APAP overdose. Method(s): This study involved the APAP and control groups (ferrous sulfate and chlorpheniramine). The APAP study group contained three subgroups of APAP with different dosage, i.e., 25 g (50 tabs)/37.5 g (75 tabs)/50 g (100 tabs). The positive control group containing ferrous sulfate, i.e., 15 g (50 tabs), has been reported previously to form pharmacobezoars in overdose. The negative control group containing chlorpheniramine, i.e., 200 mg (50 tabs), has not been reported to form pharmacobezoars in previous case studies. Tablets from each study group were placed into a separate pig stomach. Each stomach contained 28 ml USP standard simulated gastric acid. The stomach was placed in a plastic box filled with water maintaining at 37 degreeC. Each test group was examined for 4 h in the stomach. The primary outcome was the presence of clump formation. Positive clump formation was defined as tablets sticking together and the ability to maintain shape upon dissecting the pig stomach and lifting with fingers. Tablet clumps would then undergo dissolution testing with subsequent analysis of dissolution profiles. Result(s): Formation of tablets clumps was confirmed in APAP overdose in the in vitro environment. Clumps were noted to be present in the 37.5 g and 50 g APAP groups, while 25 g APAP was unlikely to form clumps. The dissolution profile of clump demonstrated slower release without reaching plateau at 60 min, as compared to corresponding individual tabs of APAP. f1 and f2 analyses showed the dissolution profile of clump was different compared to th

Objectives: There have been few studies of pharmacobezoar formation, but they can be an important contributor to overdose toxicity. Pharmacobezoars may explain the delayed peak or "double hump" pharmacokinetics, which were noted in previous case reports with delayed toxicity of acetaminophen (APAP). We validated the presence of APAP bezoar formation in a controlled modified in vitro environment simulating acute APAP overdose. Method(s): This study involved the APAP and control groups (ferrous sulfate and chlorpheniramine). The APAP study group contained three subgroups of APAP with different dosage, i.e., 25 g (50 tabs)/37.5 g (75 tabs)/50 g (100 tabs). The positive control group containing ferrous sulfate, i.e., 15 g (50 tabs), has been reported previously to form pharmacobezoars in overdose. The negative control group containing chlorpheniramine, i.e., 200 mg (50 tabs), has not been reported to form pharmacobezoars in previous case studies. Tablets from each study group were placed into a separate pig stomach. Each stomach contained 28 ml USP standard simulated gastric acid. The stomach was placed in a plastic box filled with water maintaining at 37 degreeC. Each test group was examined for 4 h in the stomach. The primary outcome was the presence of clump formation. Positive clump formation was defined as tablets sticking together and the ability to maintain shape upon dissecting the pig stomach and lifting with fingers. Tablet clumps would then undergo dissolution testing with subsequent analysis of dissolution profiles. Result(s): Formation of tablets clumps was confirmed in APAP overdose in the in vitro environment. Clumps were noted to be present in the 37.5 g and 50 g APAP groups, while 25 g APAP was unlikely to form clumps. The dissolution profile of clump demonstrated slower release without reaching plateau at 60 min, as compared to corresponding individual tabs of APAP. f1 and f2 analyses showed the dissolution profile of clump was different compared to th

Background: Utilities of pertinent clinical outcomes are crucial variables for assessing the benefits and risks of drugs, but numerical data on utilities may be unreliable or altogether missing. We propose a method to incorporate qualitative information into a probabilistic decision analysis framework for quantitative benefit-risk assessment. Objective: To investigate whether conclusive results can be obtained when the only source of discriminating information on utilities is widely agreed upon qualitative relations, for example, ''sepsis is worse than transient headache'' or ''alleviation of disease is better without than with complications.'' Method: We used the structure and probabilities of 3 published models that were originally evaluated based on the standard metric of quality-adjusted life years (QALYs): terfenadine versus chlorpheniramine for the treatment of allergic rhinitis, MCV4 vaccination against meningococcal disease, and alosetron for irritable bowel syndrome. For each model, we identified clinically straightforward qualitative relations among the outcomes. Using Monte Carlo simulations, the resulting utility distributions were then combined with the previously specified probabilities, and the rate of preference in terms of expected utility was determined for each alternative. Results: Our approach conclusively favored MCV4 vaccination, and it was concordant with the QALY assessments for the MCV4 and terfenadine versus chlorpheniramine case studies. For alosetron, we found a possible unfavorable benefit-risk balance for highly risk-averse patients not identified in the original analysis. Conclusion: Incorporation of widely agreed upon qualitative information into quantitative benefit-risk assessment can provide for conclusive results. The methods presented should prove useful in both population and individual-level assessments, especially when numerical utility data are missing or unreliable, and constraints on time or money preclude its collection., AuthorCount:4

A sensitive and selective high performance liquid chromatography-peroxyoxalate chemiluminescence (PO-CL) method has been developed for the simultaneous determination of chlorpheniramine (CPA) and monodesmethyl chlorpheniramine (MDCPA) in human serum. The method combines fluorescent labeling with 4-(4,5-diphenyl-1H-imidazole-2-yl)phenyl boronic acid using Suzuki coupling reaction with PO-CL detection. CPA and MDCPA were extracted from human serum by liquid-liquid extraction with n-hexane. Excess labeling reagent, which interfered with trace level determination of analytes, was removed by solid-phase extraction using a C18 cartridge. Separation of derivatives of both analytes was achieved isocratically on a silica column with a mixture of acetonitrile and 60 mM imidazole-HNO(3) buffer (pH 7.2; 85:15, v/v) containing 0.015% triethylamine. The proposed method exhibited a good linearity with a correlation coefficient of 0.999 for CPA and MDCPA within the concentration range of 0.5-100 ng/mL. The limits of detection (S/N = 3) were 0.14 and 0.16 ng/mL for CPA and MDCPA, respectively. Using the proposed method, CPA could be selectively determined in human serum after oral administration., Analytical and bioanalytical chemistry, 398(2), pp.823-829; 2010

A validated method for the simultaneous analysis of multiple hallucinogens, chlorpheniramine, ketamine, ritalinic acid, and several metabolites is presented. The procedure comprises a sample clean-up step, using mixed-mode solid-phase extraction followed by liquid chromatography (LC)-tandem mass spectrometry analysis. Chromatographic separation was achieved using a Sunfire C(8) column eluted with a mixture of formate buffer, methanol, and acetonitrile. The applied LC gradient ensured the elution of all the drugs examined within 14 min and produced chromatographic peaks of acceptable symmetry. Selectivity of the method was achieved by a combination of retention time and two precursor-product ion transitions for the non-deuterated analogues. Validation of the method was performed using 500 microL of urine. The limits of quantification (LOQ) for LSD and 2-oxo-3-hydroxy-LSD were 0.05 and 1 ng/mL, respectively, and ranged, for the other hallucinogens, from 0.5 to 10 ng/mL. Linear and quadratic regression was observed from the LOQ of each compound to 12.5 ng/mL for LSD, 50 ng/mL for 2-oxo-3-hydroxy-LSD and 500 ng/mL for the others (r(2) > 0.99). Precision for the QC samples, spiked at a minimum of two concentrations, was calculated [%CV and %bias < 20% for most of the compounds, except for bufotenine and cathinone (%bias < 24%), and ibogaine (%bias < 30%)]. Extraction was found to be both reproducible and efficient with recoveries > 87% for all the analytes. Furthermore, the processed samples were demonstrated to be stable in the autosampler for at least 24 h. Finally, the validated method was applied to the determination of chlorpheniramine, ketamine, LSD, and psilocin in authentic urine samples.

Chlorpheniramine, a popular nonprescription antihistaminic, is known to cause drowsiness. This side effect has a potential to impair performance and to be a factor in accidents. Therefore, this study was conducted to establish the prevalence of this drug in pilot fatalities of aviation accidents. During fatal aircraft accident investigations, postmortem samples collected from the pilots at autopsy are submitted to the Civil Aeromedical Institute for toxicological evaluation, and the findings are maintained in a database. Those data were examined for the presence of chlorpheniramine in the fatalities, which occurred during a 6-year (1991-1996) period. It was determined that there were 47 (2.2%) accidents involving chlorpheniramine. In 16 of these cases, only chlorpheniramine was found, with the mean concentrations of 109 ngml (n = 4) in blood and 1412 ng/g (n = 12) in liver. Other drugs were also present in the remaining 31 cases, wherein the mean chlorpheniramine concentrations were 93 ng/ml (n = 18) in blood and 747 ng/g (n = 12) in liver. Ninety-five percent of all the quantitative blood values were at or above the therapeutic (10 ng/ml) level, giving a 100 ng/ml (n = 21) blood mean level. The drug's mean concentration in the liver of all the cases was 1080 ng/g (n = 24). The average chlorpheniramine blood value was approximately 10 times higher than its therapeutic value. The presence of other drugs did not appear to significantly alter the blood level of chlorpheniramine, but no such correlation could be established with the hepatic value. The approximate 10-fold increase in the liver concentration, as compared with the blood value, was consistent with the general trend of the distribution of drugs in the hepatic compartment. However, the contribution of postmortem redistribution of the drug to alter its concentration cannot be entirely ruled out.

Changes in blood histamine concentrations of rhesus monkeys were measured after a 4000-rad dose of mixed gamma-neutron radiation. All animals were pretreated with amino-guanidine to retard histamine catabolism. Histamine concentrations increased from 26 + or - 13.5 to 235 + or - 16 ng/ml after irradiation. When the animals were pretreated with an antihistamine, chlorpheniramine (3 mg/kg), histamine concentrations changed from 25.7 + or - 13.5 to 462 + or - 226 ng/ml after irradiation. When the monkeys were pretreated with a specific mast cell histamine depleter, compound 48/80 (1mg/kg per day) for four consecutive days and then irradiated (4000 rads), histamine concentrations did not change significantly. When 48/80 was given 20 min after irradiation, histamine concentrations changed from 18 + or - 2 ng/ml to a maximum of 35 + or - 9 ng/ml after 48/80 injection. (Author)

Using the hydrogen washout technique, blood flow in the lateral funiculus of the spinal cord of rhesus monkeys was measured before and after a contusion sufficient to render the animals paraplegic. In untreated animals, the blood flow increased 1 hour after injury to almost twice the normal flow rate (17.6 to 31.8 ml/min per 100 g). When the animals were pretreated with histamine antagonists (chlorpheniramine, an H sub 1 antagonist, and metiamide, an H sub 2 antagonist), there was no significant increase in blood flow following contusion. Antihistamines were ineffective in preventing edema. (Author)

The hypotensive response of monkeys to exogenous histamine was measured when the histamine was given without antagonist, after chlorpheniramine (10 mg/kg) or mepyramine (10 mg/kg), and after these two antagonists in combination with burimamide (20 mg/kg). The dose of histamine needed to elicit a 50 percent maximal response was: without antagonist, 0.115 micrograms/kg; after chlorpheniramine, 13.5 micrograms/kg; after chlorpheniramine and burimamide, 23.5 micrograms/kg; after mepyramine, 23.0 micrograms/kg; and after mepyramine and burimamide, 55.0 micrograms/kg.