Adults who are HIV-positive and take an antiretroviral cocktail containing Viramune and who also are on methadone therapy to treat drug addiction might have to have their methadone doses increased because of interactions between the medications, researchers in Germany report.
The scientists examined 20 HIV patients taking both Viramune and methadone and discovered that among some of the study subjects methadone absorption into the bloodstream was severely suppressed. Blood-based methadone levels fell by an average of 29%, but absorption of the drug dropped as much as 70% in some HIV patients. All but six patients required higher methadone doses to prevent drug-withdrawal symptoms.
Because blood-based levels of Viramune were unaffected, the researchers say the medications can be prescribed together as long as methadone doses are adjusted as needed for full efficacy.
