Methadone serum levels can be reduced by
amprenavir, nelfinavir,
lopinavir/ritonavir, ritonavir/saquinavir, tipranavir/ritonavir and possibly
ritonavir. Not all patients appear to be affected. Amprenavir levels may be reduced by
methadone.
An increased
methadone dosage may be needed in some patients to prevent opiate withdrawal. Monitor
amprenavir to ensure it remains effective. It has been suggested that alternative antiretrovirals should be considered.