Methadone Interferons

Contraindications to interferon alfa therapy include hepatic decompensation, autoimmune disease, and history of cardiac arrhythmia. Caution is advised in the setting of psychiatric disease, epilepsy, thyroid disease, ischemic cardiac disease, severe renal insufficiency, and cytopenia. Alfa interferons are abortifacient in primates and should not be administered in pregnancy. Potential drug-drug interactions include increased theophylline levels and increased methadone levels. Co-administration with didanosine is not recommended because of a risk of hepatic failure, and co-administration with zidovudine may exacerbate cytopenias. 

Schafer M, Boetsch T, Laakmann G. Psychosis in a methadone-substituted patient during interferon-alpha treatment of hepatitis C. Addiction 2000 95(7) 1101-4. 

Peginterferon alfa does not affect the pharmacokinetics of methadone, but an isolated report describes a patient who relapsed to heroin use following treatment with peginterferon. Methadone maintenance does not appear to affect the pharmacokinetics of peginterferon alfa or the virological response to interferons. Similarly, buprenorphine does not appear to influence the effect of interferon. 

Mauss S, Berger F, Goelz J, Jacob B, SchmutzG. Aprospective controlled stucfy of interferon-based therapy of chronic hepatitis C in patients on methadone maintenance. Hepatology (2004) 40, 120-4. 

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