Literature Collection

OBJECTIVE: To estimate the prevalence of ever, current and heavy tobacco and alcohol use and their correlates among patients undergoing methadone maintenance treatment (MMT). DESIGN: Cross-sectional study. SETTING: The study was conducted in all of the 5 MMT clinics in Dehong Prefecture, China. PARTICIPANTS: 2121 (81.6%) eligible MMT participants were included in the study population. ANALYSIS: Ordinal logistic regression was used to estimate the ORs and their 95% CIs. RESULTS: The overall prevalence of ever, current and heavy smoking was 98.6%, 97.8% and 66.3%, respectively; while that of ever, current and hazardous alcohol drinking was 86.6%, 58.6% and 16.6%, respectively. Among HIV-infected participants, the proportions of those experiencing harmful effects of tobacco and alcohol on AIDS were 53.6% and 72.5%, respectively, and 16.9% and 49.3% had ever tried to quit after diagnosis with HIV. After adjusting for potential confounders, heavier smokers and more hazardous drinkers were more likely to be men, older and less educated. Ethnic minorities were less likely to heavily smoke, but more likely to engage in hazardous drinking. In addition, hazardous drinking was negatively associated with longer years of MMT and HIV infection. Moreover, heavier smoking (OR>/=2=2.08, 95% CI 1.16 to 3.73) and more hazardous drinking (OR>/=2=2.46, 95% CI 1.53 to 3.97) were positively associated with having multiple sexual partners, and both were positively associated with each other. CONCLUSIONS: The prevalence of tobacco and alcohol consumption was extraordinarily high among MMT participants in China, suggesting the urgent need of enhancing MMT patients' awareness of the harmful effects of tobacco and alcohol consumption and implementing comprehensive education and effective intervention programmes.

BACKGROUND: Despite the World Health Organization listing methadone as an essential medication, effective dose selection is challenging, especially in racial and ethnic minority populations. Subtherapeutic doses can result in withdrawal symptoms while supratherapeutic doses can result in overdose and death. Although CYP3A4 was conventionally considered the principal methadone metabolizing enzyme, more recent data have identified CYP2B6 as the principal enzyme. CYP2B6 has ethnically-associated polymorphisms that affect the metabolic rate. Our objective was to investigate the effects of genetic and nongenetic factors on methadone metabolism. METHODS: We measured trough plasma methadone levels in 100 participants with opioid use disorder. We assessed methadone metabolism by calculating the metabolite ratio (major metabolite: 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine [EDDP] divided by methadone concentration). We assessed hepatic fibrosis and steatosis by transient elastography and CYP2B6 alleles, principally responsible for methadone metabolism. Mixed effects models modeled the data in 97 participants. RESULTS: Participants were largely male (58%), minority (61% African American) and non-Hispanic (68%). Forty percent were HCV mono-infected, 40% were uninfected, and 20% were HCV/HIV co-infected. Female sex had significant effects on (R)- and (S)-methadone metabolism (p = 0.016 and p = 0.044, respectively). CYP2B6 loss of function (LOF) alleles significantly affected (S)-methadone metabolism (p = 0.012). Body mass index (BMI) significantly affected (R)-methadone metabolism (p = 0.034). Methadone metabolism appeared to be lower in males, in individuals with LOF alleles, and elevated BMI. CONCLUSIONS: Genetic analysis, especially in minority populations, is essential to delivering individualized treatments. Although the principal methadone metabolizing enzyme remains controversial, our results suggest that sex, CYP2B6 genotype, and BMI should be incorporated into multivariate models to create methadone dosing algorithms. Methadone dosing algorithms should facilitate medication delivery, improve patient satisfaction, and diminish overdose potential.