Pharmacogenetics of alcohol addiction: current perspectives

The role of alcohol intake in the pharmacogenetics of treatment with clozapine

Clozapine (CLZ) is an atypical antipsychotic reserved for patients with refractory psychosis, but it is associated with a significant risk of severe adverse reactions (ADRs) that are potentiated with the concomitant use of alcohol. Additionally, pharmacogenetic studies have explored the influence of several genetic variants in CYP450, receptors and transporters involved in the interindividual response to CLZ. Herein, we systematically review the current multiomics knowledge behind the interaction between CLZ and alcohol intake, and how its concomitant use might modulate the pharmacogenetics. CYP1A2*1F, *1C and other alleles not yet discovered could support a precision medicine approach for better therapeutic effects and fewer CLZ ADRs. CLZ monitoring systems should be amended and include alcohol intake to protect patients from severe CLZ ADRs.

Pharmacogenetics of Addiction Therapy

Drug addiction is a serious relapsing disease that has high costs to society and to the individual addicts. Treatment of these addictions is still in its nascency, with only a few examples of successful therapies. Therapeutic response depends upon genetic, biological, social, and environmental components. A role for genetic makeup in the response to treatment has been shown for several addiction pharmacotherapies with response to treatment based on individual genetic makeup. In this chapter, we will discuss the role of genetics in pharmacotherapies, specifically for cocaine, alcohol, and opioid dependences. The continued elucidation of the role of genetics should aid in the development of new treatments and increase the efficacy of existing treatments.

Effects of CYP2C19*17 Genetic Polymorphisms on the Steady-State Concentration of Diazepam in Patients With Alcohol Withdrawal Syndrome

Background: Diazepam is one of the most widely prescribed tranquilizers for the therapy of alcohol withdrawal syndrome (AWS), which includes the symptoms of anxiety, fear, and emotional tension. However, diazepam therapy often turns out to be ineffective, and some patients experience dose-dependent adverse drug reactions, reducing the efficacy of therapy. Aim: The purpose of our study was to investigate the effects of CYP2C19*17 genetic polymorphisms on the steady-state concentration of diazepam in patients with AWS. Materials and Methods: The study was conducted on 50 Russian male patients suffering from the AWS. For the therapy of psychomotor agitation, anxiety, fear, and emotional tension, patients received diazepam in injections at a dosage of 30.0 mg/day for 5 days. Genotyping was performed by real-time polymerase chain reaction. The efficacy and safety assessment was performed using psychometric scales and scales for assessing the severity of adverse drug reactions. Therapeutic drug monitoring (TDM) was performed using the high-performance liquid chromatography-mass spectrometry (HPLC-MS/MS) method. Results: Based on the results of the study, we revealed the differences in the efficacy of therapy in patients with different CYP2C19 -806C>T genotypes: (*1/*1) -12.0 [-15.0; -8.0], (*1/*17+*17/*17) -7.0 [-14.0; -5.0], P < .001, as well as the results of TDM: (CC) 250.70 [213.34; 308.53] ng/mL (*1/*17+*17/*17) 89.12 [53.26; 178.07] ng/mL, P < .001. Conclusion: Thus, our study enrolling 50 patients with AWS, showed the effects of CYP2C19*17 genetic polymorphisms on the efficacy and safety rates of diazepam. Furthermore, we revealed the statistically significant difference in the levels of plasma steady-state concentrations of diazepam in patients carrying different genotypes.

Real-world effectiveness of pharmacological treatments of alcohol use disorders in a Swedish nation-wide cohort of 125 556 patients

BACKGROUND AND AIM

Pharmacotherapy for alcohol use disorder (AUD) is recommendable, but under-used, possibly due to deficient knowledge of medications. This study aimed to investigate the real-world effectiveness of approved pharmacological treatments (disulfiram, acamprosate, naltrexone and nalmefene) of AUD.

DESIGN

A nation-wide, register-based cohort study.

SETTING

Sweden.

PARTICIPANTS

All residents aged 16-64 years living in Sweden with registered first-time treatment contact due to AUD from July 2006 to December 2016 (n = 125 556, 62.5% men) were identified from nation-wide registers.

MEASUREMENTS

The main outcome was hospitalization due to AUD. The secondary outcomes were hospitalization due to any cause, alcohol-related somatic causes, as well as work disability (sickness absence or disability pension), and death. Mortality was analysed with between-individual analysis using a traditional multivariate-adjusted Cox hazards regression model. Recurrent outcomes, such as hospitalization-based events and work disability, were analysed with within-individual analyses to eliminate selection bias.

FINDINGS

Naltrexone combined with acamprosate [hazard ratio (HR) = 0.74; 95% confidence interval (CI) = 0.61-0.89], combined with disulfiram (HR = 0.76, 95% CI = 0.60-0.96) and as monotherapy (HR = 0.89, 95% CI = 0.81-0.97) was associated with a significantly lower risk of AUD-hospitalization compared with no use of AUD medication. Similar results were found for risk of hospitalization due to any cause. Benzodiazepine use and acamprosate monotherapy were associated with an increased risk of AUD-hospitalization (HR = 1.18, 95% CI = 1.14-1.22 and HR = 1.10, 95% CI = 1.04-1.17, respectively). No statistically significant effects were found for work disability or mortality.

CONCLUSIONS

Naltrexone as monotherapy and when combined with disulfiram and acamprosate appears to be associated with lower risk of hospitalization due to any and alcohol-related causes, compared with no use of alcohol use disorder (AUD) medication. Acamprosate monotherapy and benzodiazepine use appear to be associated with increased risk of AUD-associated hospitalization.

CYP3A subfamily activity affects the equilibrium concentration of Phenazepam® in patients with anxiety disorders and comorbid alcohol use disorder

Phenazepam^® is prescribed to relieve anxiety and sleep disorders during alcohol withdrawal, although it is associated with undesirable side effects. Aim: To demonstrate changes in the safety and efficacy profiles of Phenazepam in patients with anxiety disorders and comorbid alcohol use disorder. Materials & methods: A total of 94 Russian patients with alcohol use disorder received 4.0 mg of Phenazepam per day in tablets. We used a urinary 6-beta-hydroxycortisol/cortisol ratio to evaluate CYP3A activity. Results: A statistically significant inverse correlation between Phenazepam plasma concentration and CYP3A activity was found (r = -0.340 and p = 0.017). Correlation between the concentration/dose ratio and phenotyping results was also statistically significant (r = 0.301 and p = 0.026). Conclusion: The safety and efficacy of Phenazepam depend on CYP3A genetic polymorphisms.