Atazanavir and Norethindrone interaction
Atazanavir 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 Atazanavir (REYATAZ) label · effective 2024-12-05
Hormonal contraceptives: ethinyl estradiol and norgestimate or norethindrone ↓ ethinyl estradiol ↑ norgestimate c ↑ ethinyl estradiol ↑ norethindrone d Use caution if considering coadministration of oral contraceptives with REYATAZ or REYATAZ with ritonavir.
If REYATAZ with ritonavir is coadministered with an oral contraceptive, it is recommended that the oral contraceptive contain at least 35 mcg of ethinyl estradiol.
If REYATAZ is administered without ritonavir, the oral contraceptive should contain no more than 30 mcg of ethinyl estradiol.
Coadministration of REYATAZ or REYATAZ with ritonavir and other hormonal contraceptives (eg, contraceptive patch, contraceptive vaginal ring, or injectable contraceptives) or oral contraceptives containing progestogens other than norethindrone or norgestimate, or less than 25 mcg of ethinyl estradiol, has not been studied; therefore, alternative methods of contraception…
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.