Methadone is widely used for the treatment of opioid dependence. Although in most countries the drug is administered as a racemic mixture of (R)- and (S)- methadone, (R)-methadone accounts for most, if not all, of the opioid effects. Methadone can be detected in the blood 15-45 minutes after oral administration, with peak plasma concentration at 2.5-4 hours. Methadone has a mean bioavailability...

BACKGROUND Methadone maintenance therapy (MMT) is a mainstay for treating opioid use disorder and preventing and managing HIV among people who inject drugs (PWID). While previous research suggested low dosing of methadone and high rates of discontinuation of MMT among PWID in Thailand, little is known about patients' lived experiences with MMT in this setting. Therefore, we conducted a mixed-me...

AIM To quantify gender, age-group and quantity of methadone prescribed as risk factors for drugs-related deaths (DRDs), and for methadone-specific DRDs, in Scotland's methadone-prescription clients. DESIGN Linkage to death-records for Scotland's methadone-clients with one or more Community Health Index (CHI)-identified methadone prescriptions during July 2009 to June 2013. SETTING Scotland'...

OBJECTIVE To investigate the pharmacokinetics (PK) and PK- pharmacodynamic (PD) relationship of methadone in a cohort of outpatients undergoing methadone maintenance treatment (MMT). METHODS Sixty male patients undergoing MMT with a mean ±SD methadone daily dosage of 58 ± 34 mg were enrolled in this study. A 5-ml blood sample was collected before the daily intake of methadone. As a PD measure...

There has been recent concern about the association between high dose methadone and prolongation of QTc in the electrocardiogram. QTc is the time from the beginning of the QRS complex to the end of the T have as measured on an electrocardiogram and corrected for heart rate. To date, no association has been made between methadone and buprenorphine in commonly used doses and prolonged QTc. Electr...

BACKGROUND Buprenorphine is used in the treatment of opioid dependence. Due to its pharmacology, the transfer from methadone to buprenorphine may precipitate withdrawal symptoms. METHODS Methadone maintained patients with clinical indicators of stability who were seeking withdrawal from methadone were recruited from three Australian states. Patients on methadone doses between 30 and 40 mg wer...

Methadone is a long-acting opioid with considerable unexplained interindividual variability in clearance. Cytochrome P450 2B6 (CYP2B6) mediates clinical methadone clearance and metabolic inactivation via N-demethylation to 2-ethyl-1,5-dimethyl3,3-diphenylpyrrolidine (EDDP). Retrospective studies suggest that individuals with the CYP2B6*6 allelic variant have higher methadone plasma concentratio...

OBJECTIVES This case report aims to help healthcare providers and methadone clinic patients to recognize one of the less recognized adverse effects of methadone, hyperhidrosis, and to suggest oxybutynin as a possible solution. METHODS A 35-year-old man on methadone maintenance therapy presented with excessive sweating, which began promptly after methadone was introduced. Urine toxicology was ...

Methadone is a mu-opioid receptor agonist used for treating opiate dependence. The range of effective methadone doses is broad. Part of the large inter-individual variability in efficacy may be accounted for by genetic factors. Methadone is a substrate of the transporter P-glycoprotein (P-gp) 170 that is encoded by the ABCB1 (MDR1) gene. Thus, P-gp variants may play a role in methadone absorpti...

AIMS To perform a toxicological analysis of deaths involving methadone and to determine the fatal concentration of methadone in such deaths. METHODS Deaths in which methadone was mentioned in the cause of death were identified. Deaths were divided into those associated with methadone only and deaths in which the cause of death was a combination of methadone and other drugs. Toxicological find...