Coadministration of sofosbuvir and an oral contraceptive containing ethinyl estradiol and norgestimate increased ethinyl estradiol Cmax and AUC by 14% and 8%. The Cmax and AUC of norgestromin increased by 6% and 5%, whereas the Cmax and AUC of norgestrel increased by 18% and 19%.

Based on drug interaction studies conducted with sofosbuvir, no clinically significant drug interactions have been observed or are expected when sofosbuvir is combined with oral contraceptives.
Coadministration of sofosbuvir (400 mg, once daily) and an oral contraceptive containing ethinyl estradiol (0.025 mg once daily) and norgestimate (0.18/0.215/0.25, once daily) increased ethinyl estradiol Cmax and AUC by 15% and 9%. but reduced Cmin by 1%. The Cmax, AUC, and Cmin of norgestromin increased by 7%, 6% and 7%, respectively., The Cmax, AUC, and Cmin of norgestrel increased by 18%, 19%, and 23%, respectively.