US FDA announces important changes in amprenavir product labelling
Please note that product labelling has been changed for amprenavir (Agenerase) capsules and amprenavir oral solution to reflect new precautions related to use of amprenavir with methadone, and with oral (hormonal) contraceptives.
Methadone: Coadministration of amprenavir and methadone can decrease plasma levels of methadone. Amprenavir may be less effective due to decreased amprenavir plasma concentrations in patients taking these agents together. Alternative antiretroviral therapy should be considered. Dosage of methadone may need to be increased when coadministered with amprenavir.
Oral contraceptives: (Ethinyl estradiol/norethindrone) Those taking amprenavir should be instructed not to use hormonal contraceptives because some birth control pills (those containing ethinyl estradiol/norethindrone) have been found to decrease the concentration of amprenavir. This may lead to loss of virologic response and possible resistance to amprenavir. Alternative methods of non-hormonal contraception are recommended.