CYP2C19 genetics in fatal carisoprodol intoxications

Polysubstance Use in Adults With Opioid Use Disorder Receiving Buprenorphine Maintenance

INTRODUCTION

Studying polysubstance use is a public health recommendation. In the United Arab Emirates, more than 80% of adults with opioid use disorder (OUD) use 2 or more nonopioid substances. This secondary analysis contrasts the characteristics of polysubstance users (OUD + ≥1 nonopioid) with OUD, explores the correlates and predictors of nonfatal overdose, and examines the impact of polysubstance use on OUD treatment outcomes using buprenorphine (BUP).

METHODS

This analysis uses data from a 16-week outpatient randomized controlled trial of 141 adults with OUD allocated to BUP + incentivized adherence and abstinence monitoring (n = 70) and BUP in usual care (control, n = 71). Outcomes were nonfatal overdose events over the preceding 12 months, positive drug screens, and treatment retention. Participant characteristics were contrasted, and bivariate statistical tests were conducted for simple associations followed by logistic regression.

RESULTS

Polysubstance use was reported by 117 participants (82.9%), the majority of whom used pregabalin 72.1% (n = 75). Compared with OUD, polysubstance users observed higher arrests (median, 1.0 [interquartile range, 0.0-3.0] vs 0.5 [interquartile range, 0.0-2.0]; P = 0.04]) and nonfatal overdose events (n = 33 [31.8%] vs 2 [10.8%], P = 0.003). Carisoprodol and injecting drug use independently predicted nonfatal overdose (adjusted odds ratio, 4.519 [95% confidence interval, 1.81-11.22] and 2.74 [95% confidence interval, 1.15-6.51], respectively). No significant difference was observed in opioid use and retention in treatment outcomes between groups.

CONCLUSION

Carisoprodol and injecting drug use increase the likelihood of nonfatal overdose in adults with OUD. Polysubstance use does not impact response to BUP treatment compared with OUD.

Single and Multiple Dose PK–PD Characterization for Carisoprodol. Part I: Pharmacokinetics, Metabolites, and 2C19 Phenotype Influence. Double-Blind, Placebo-Controlled Clinical Trial in Healthy Volunteers

Carisoprodol was authorised in 1959 without a full pharmacokinetic–pharmacodynamic (PK–PD) characterisation. We designed a crossover, double-blind, placebo-controlled, randomized clinical trial to characterize the PKs of carisoprodol and its main active metabolite, meprobamate, after single (350 mg), multiple (350 mg/8 h, 14 days), and double (700 mg) doses of carisoprodol. Thirteen healthy volunteers were enrolled. After a single (350 mg) dose, the main carisoprodol parameters were (mean ± SD) Cmax: 2580 ± 1214 ng/mL, AUC_0–∞: 8072 ± 6303 h·ng/mL, and half-life (T_1/2): 2 ± 0.8 h. For meprobamate, the parameters were Cmax: 2181 ± 605 ng/mL and 34,529 ± 7747 h·ng/mL y 9 ± 1.9 h. Different profiles were found for extensive and poor 2C19 metabolizers. After 14 days of treatment (350 mg/8 h) the results for carisoprodol were (mean ± SD) Cmax: 2504 ± 730 ng/mL, AUC_0–∞: 7451 ± 3615 h·ng/mL, and T_1/2: 2 ± 0.7 h. For meprobamate (a steady state was reached), the parameters were Cmax: 5758 ± 1255 ng/mL and 79,699 ± 17,978 h·ng/mL y 8.7 ± 1.4 h. The study allowed for the full characterization of the pharmacokinetic profile of carisoprodol and meprobamate. Accumulation of meprobamate but not of carisoprodol was evident after 14 days of treatment.

Pharmacogenetics and Forensic Toxicology: A New Step towards a Multidisciplinary Approach

Pharmacogenetics analyzes the individual behavior of DNA genes after the administration of a drug. Pharmacogenetic research has been implemented in recent years thanks to the improvement in genome sequencing techniques and molecular genetics. In addition to medical purposes, pharmacogenetics can constitute an important tool for clarifying the interpretation of toxicological data in post-mortem examinations, sometimes crucial for determining the cause and modality of death. The purpose of this systematic literature review is not only to raise awareness among the forensic community concerning pharmacogenetics, but also to provide a workflow for forensic toxicologists to follow in cases of unknown causes of death related to drug use/abuse. The scientific community is called on to work hard in order to supply evidence in forensic practice, demonstrating that this investigation could become an essential tool both in civil and forensic contexts. The following keywords were used for the search engine: (pharmacogenetics) AND (forensic toxicology); (pharmacogenetics) AND (post-mortem); (pharmacogenetics) AND (forensic science); and (pharmacogenetics) AND (autopsy). A total of 125 articles were collected. Of these, 29 articles were included in this systematic review. A total of 75% of the included studies were original articles (n = 21) and 25% were case reports (n = 7). A total of 78% (n = 22) of the studies involved deceased people for whom a complete autopsy was performed, while 22% (n = 6) involved people in good health who were given a drug with a subsequent pharmacogenetic study. The most studied drugs were opioids (codeine, morphine, and methadone), followed by antidepressants (tricyclic antidepressants and venlafaxine). Furthermore, all studies highlighted the importance of a pharmacogenetics study in drug-related deaths, especially in cases of non-overdose of drugs of abuse. This study highlights the importance of forensic pharmacogenetics, a field of toxicology still not fully understood, which is of great help in cases of sudden death, deaths from overdose, deaths after the administration of a drug, and also in cases of complaint of medical malpractice.