Association of ABCB1, μ-opioid Receptor, and Cytochrome P450 Genes with Methadone Dose in Iranian Male Addicts Under Methadone Therapy

Introduction: Treatment of opioid use disorders (OUDs) via safe and effective approaches has been investigated for years. Methadone maintenance treatment (MMT) has been considered an effective therapy for opioid addiction. It has been observed that patients with genetic polymorphisms often show variability in the optimal drug dose requirement and treatment schedule. This study aimed to investigate the relationship between single nucleotide polymorphisms (SNPs) in the ATP-binding cassette subfamily B member-1 (ABCB1), the mu-opioid receptor (OPRM1), and cytochrome P450 (CYP) genes and methadone dose in patients undergoing MMT in Mazandaran Province, Iran. Methods: In a cross-sectional study, 216 male MMT patients (20 to 45 years old) who were involved in the treatment program for at least three months were randomly recruited from six MMT clinics in Mazandaran province between 2018 and 2020. Blood samples were taken, DNA was extracted, and SNPs of CYP2B6 (G516T, A785G), CYP2C19 (-3402C T), CYP3A4 (-392A G), OPRM (A118G), and ABCB1 (C3435T, G2677T, G2677A, and C1236T) genes were evaluated using polymerase chain reaction-restriction fragment length polymorphism (RFLP). Results: Our results showed no significant relationship between all the studied genotypes and methadone dose requirements. Conclusion: The present study, for the first time in the Mazandaran population, reported no significant correlations between methadone dose requirement and different SNPs in the ABCB1, OPRM1, and CYP genes in MMT patients, which is consistent with other studies conducted on the Iranian population.