Fosamprenavir and Norethindrone interaction
Fosamprenavir and Norethindrone: both prescribing labels describe an interaction that usually calls for monitoring, a dose change, or spacing the doses.
Usually manageable with monitoring or a dose change. Tell your pharmacist you take both.
What the FDA labels say
From the Norethindrone label · effective 2026-01-31
Substances increasing the systemic concentrations of HCs: Co-administration of certain HCs and strong or moderate CYP3A4 inhibitors such as itraconazole, voriconazole, fluconazole, grapefruit juice, or ketoconazole may increase the systemic concentrations of progestins, including norethindrone.
…inhibitors and nonnucleoside reverse transcriptase inhibitors: Significant decreases in systemic concentrations of progestin have been noted in cases of co-administration with some HIV protease inhibitors (e.g., nelfinavir, ritonavir, darunavir/ritonavir, (fos)amprenavir/ritonavir, lopinavir/ritonavir, and tipranavir/ritonavir), some HCV protease inhibitors (e.g.,…
In contrast, significant increases in systemic exposure of the progestin have been noted in cases of co-administration with certain other HIV protease inhibitors (e.g., indinavir and atazanavir/ritonavir) and with other non-nucleoside reverse transcriptase inhibitors (e.g., etravirine).
From the Fosamprenavir (Fosamprenavir Calcium) label · effective 2026-06-30
Oral contraceptives: Ethinyl estradiol/norethindrone a Alternative methods of non-hormonal contraception are recommended.
Taking more than these two? Interactions stack. Check your whole list at once; it stays in your browser.
Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.