Levothyroxine and Norgestimate and ethinyl estradiol interaction
Levothyroxine and Norgestimate and ethinyl estradiol: 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 Levothyroxine (Levothyroxine Sodium) label · effective 2024-07-10
…1: Drugs That May Alter T 4 and Triiodothyronine (T 3 ) Serum Transport Without Effecting Free Thyroxine (FT 4 ) Concentration (Euthyroidism) Drug or Drug Class Effect Clofibrate Estrogen-containing oral contraceptives Estrogens (oral) Heroin/Methadone 5-Fluorouracil Mitotane Tamoxifen These drugs may increase serum thyroxine-binding globulin (TBG) concentration.
Pregnancy, infectious hepatitis, estrogens, estrogen containing oral contraceptives, and acute intermittent porphyria increase TBG concentrations.
From the Norgestimate and ethinyl estradiol (MONO-LINYAH) label · effective 2026-06-23
The dose of replacement thyroid hormone or cortisol therapy may need to be increased.
Women on thyroid hormone replacement therapy may need increased doses of thyroid hormone because the serum concentration of thyroid-binding globulin increases with use of COCs.
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.