Methadone
plasma levels can be markedly reduced by
efavirenz or
nevirapine, and methadone withdrawal
symptoms have been seen.
If
efavirenz or
nevirapine are added to established treatment with methadone, be alert for evidence of opiate withdrawal, and raise the methadone dose accordingly. Some patients may require an increase in the methadone dose frequency to twice daily. In patients who subsequently discontinue the NNRTI, the methadone dose should be gradually reduced.