Bile Duct Dilatation in Patients With Chronic Viral Hepatitis on Maintenance Methadone Therapy

Methadone maintenance therapy (MMT) is commonly used in the treatment of opioid dependence. Several small-scale reports have suggested that methadone may lead to nonobstructive dilatation of the common bile duct (CBD). We present the first large study to retrospectively evaluate this hypothesis in asymptomatic patients with chronic hepatitis on long-term MMT. Methods: Charts of all adult patients with chronic hepatitis with and without MMT between 2002 and 2007 at Beth Israel Medical Center were reviewed. Data collected included age, gender, CBD size, presence of cirrhosis, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, bilirubin, and dose and duration of methadone use. Patients with a history of pancreatitis and cholecystectomy were excluded. Results: CBD size in the MMT group (n=215) was significantly increased compared to controls (n=108; 5.87 mm vs 3.79 mm; P<.0001). CBD dilatation (CBD ≥8 mm) was seen in 26.1% and 2.78% of MMT and control groups, respectively (P<.0001), and was significantly associated with duration of methadone use (P=.01), but not with methadone dose (P=.83). Multivariate logistic regression showed that patients on MMT are 17.5 times more likely to develop CBD dilatation (odds ratio, 17.5). Conclusion: Chronic MMT is associated with CBD dilatation and should be considered in the differential diagnosis of asymptomatic CBD dilatation. Less invasive studies such as magnetic resonance cholangiopancreatography or endoscopic ultrasound should be considered over endoscopic retrograde cholangiopancreatography in patients without clinical or laboratory evidence suggesting biliary obstruction.