Coadministration with etonogestrel as a combined vaginal ring (CVR) has not been studied but based on metabolism and clearance a clinically significant interaction is unlikely. Etonogestrel is metabolized by CYP3A4 and is coformulated in the CVR with ethinylestradiol which is released at a dose of 0.015 mg/day. Ethinylestradiol is mainly metabolized by hydroxylation. Grazoprevir is only a weak inhibitor of CYP3A4 and is unlikely to affect this pathway to any clinically significant extent. Coadministration of ethinylestradiol and levonorgestrel as an oral contraceptive (0.03/0.15 mg single dose) and elbasvir (50 mg once daily) increased ethinylestradiol AUC and Cmax by 1% and 10%; coadministration with grazoprevir (200 mg once daily) increased ethinylestradiol AUC and Cmax by 10% and 5%. Additionally, drug interaction studies investigating safety and tolerability of coadministration of elbasvir/grazoprevir with ethinylestradiol and levonorgestrel in healthy females reported no increased incidence of notable adverse effects or liver function abnormalities and concluded that this combination can be safely co-administered with oral contraceptives.