Inducers of liver enzymes can increase the metabolism of<unk>  and etonogestrel and reduce their circulating levels. This may result in contraceptive failure. Examples of liver enzyme inducers include barbiturates (e.g., phenobarbital), bosentan, carbamazepine, efavirenz, phenytoin, primidone, rifampicin, and possibly also felbamate, griseofulvin, oxcarbazepine, rifabutin, St. John's Wort, and topiramate. Many antivirals for HIV/AIDS and HCV, such as boceprevir, nelfinavir, nevirapine, ritonavir, and telaprevir, may increase or decrease levels of<unk>  and etonogestrel. CYP3A4 inhibitors including strong inhibitors like clarithromycin, itraconazole, and ketoconazole and moderate inhibitors like diltiazem, erythromycin, and fluconazole may increase levels of<unk>  and etonogestrel. Hormonal contraceptives may interfere with the metabolism of other drugs, resulting in increased levels (e.g., ciclosporine) or decreased levels (e.g., lamotrigine).
Desogestrel
Gestodene
Levonorgestrel
Etonogestrel
Norgestrel
Hexestrol
Chloroethynylnorgestrel
Fosfestrol