CHICAGO, IL - AT Forum exclusive; October 2000 - According to 2 recently released clinical studies, hepatitis C virus (HCV) appears to significantly increase the methadone dose requirement of afflicted patients in methadone maintenance treatment (MMT) programs.

Drs. Marc Shinderman and Sarz Maxwell of the Center for Addictive Problems in Chicago, Illinois, reported at a conference in Italy last May that their HCV-positive MMT patients required 50% higher average methadone doses than a comparison group testing HCV negative (179 mg/d vs 119 mg/d; P < 0.001). In a separate research study to be published this December in the journal Heroin Addiction & Related Clinical Problems, Drs. Lubomir Okruhlica and Danica Klempova of Bratislava, Slovak Republic, report a 29% increase in average daily methadone requirement among HCV-positive patients (136 mg/d vs 105 mg/d; P < 0.01).

In both studies, the researchers speculate that HCV may in some way induce P450 liver enzymes leading to more rapid metabolism of methadone. However, this appears contrary to other research, which suggests that the virus would impair metabolic function in the liver, thus increasing methadone levels in the body and requiring a lowering of daily methadone dose rather than an increase.

This paradoxical phenomenon was unexpected, but implies that patients with HCV may require higher methadone doses than usual, and previously stable MMT patients who unexpectedly appear to need a dose increase should be immediately tested for HCV. These same effects would be expected with LAAM and buprenorphine, which also undergo first past metabolism in the liver, but data have not been reported. Watch for an article with further information in the upcoming fall edition of Addiction Treatment Forum.

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