Extreme Duration of Diazepam-Associated Sedation in a Patient With Alcohol Delirium and CYP2C19 Polymorphisms

The Role of Pharmacogenetics in Personalizing the Antidepressant and Anxiolytic Therapy

Pharmacotherapy for neuropsychiatric disorders, such as anxiety and depression, has been characterized by significant inter-individual variability in drug response and the development of side effects. Pharmacogenetics, as a key part of personalized medicine, aims to optimize therapy according to a patient's individual genetic signature by targeting genetic variations involved in pharmacokinetic or pharmacodynamic processes. Pharmacokinetic variability refers to variations in a drug's absorption, distribution, metabolism, and elimination, whereas pharmacodynamic variability results from variable interactions of an active drug with its target molecules. Pharmacogenetic research on depression and anxiety has focused on genetic polymorphisms affecting metabolizing cytochrome P450 (CYP) and uridine 5'-diphospho-glucuronosyltransferase (UGT) enzymes, P-glycoprotein ATP-binding cassette (ABC) transporters, and monoamine and γ-aminobutyric acid (GABA) metabolic enzymes, transporters, and receptors. Recent pharmacogenetic studies have revealed that more efficient and safer treatments with antidepressants and anxiolytics could be achieved through genotype-guided decisions. However, because pharmacogenetics cannot explain all observed heritable variations in drug response, an emerging field of pharmacoepigenetics investigates how epigenetic mechanisms, which modify gene expression without altering the genetic code, might influence individual responses to drugs. By understanding the epi(genetic) variability of a patient's response to pharmacotherapy, clinicians could select more effective drugs while minimizing the likelihood of adverse reactions and therefore improve the quality of treatment.

Clinical Impact of the CYP2C19 Gene on Diazepam for the Management of Alcohol Withdrawal Syndrome

Diazepam is a benzodiazepine widely prescribed for the management of patients with severe alcohol withdrawal syndrome to prevent agitation, withdrawal seizures, and delirium tremens. Despite standard dosing of diazepam, a subset of patients experience refractory withdrawal syndromes or adverse drug reactions, such as impaired motor coordination, dizziness, and slurred speech. The CYP2C19 and CYP3A4 enzymes play a key role in the biotransformation of diazepam. Given the highly polymorphic nature of the CYP2C19 gene, we reviewed the clinical impact of variants in the CYP2C19 gene on both the pharmacokinetics of diazepam and treatment outcomes related to the management of alcohol withdrawal syndrome.

How do CYP2C19*2 and CYP2C19*17 genetic polymorphisms affect the efficacy and safety of diazepam in patients with alcohol withdrawal syndrome?

Background Diazepam is one of the most commonly prescribed tranquilizers for therapy of alcohol withdrawal syndrome (AWS). Despite its popularity, there is currently no precise information on the effect of genetic polymorphisms on its efficacy and safety. The objective of our study was to investigate the effect of CYP2C19*2 and CYP2C19*17 genetic polymorphisms on the efficacy and safety of diazepam in patients with AWS. Methods The study was conducted on 30 Russian male patients suffering from the AWS who received diazepam in injections at a dosage of 30.0 mg/day for 5 days. The efficacy and safety assessment was performed using psychometric scales and scales for assessing the severity of adverse drug reactions. Results Based on the results of the study, we revealed the differences in the efficacy of therapy in patients with different CYP2C19 681G>A (CYP2C19*2, rs4244285) genotypes: (CYP2C19*1/*1) -8.5 [-15.0; -5.0], (CYP2C19*1/*2 and CYP2C19*2/*2) -12.0 [-13.0; -9.0], p = 0.021. The UKU scale scores, which were used to evaluate the safety of therapy, were also different: (CYP2C19*1/*1) 7.0 [6.0; 12.0], (CYP2C19*1/*2 and CYP2C19*2/*2) 9.5 [8.0; 11.0], p = 0.009. Patients carrying different CYP2C19 -806C>T (CYP2C19*17, rs12248560) genotypes also demonstrated differences in therapy efficacy and safety rates. Conclusions Thus, the effects of CYP2C19*2 and CYP2C19*17 genetic polymorphisms on the efficacy of diazepam were demonstrated.