Ethynodiol diacetate and ethinyl estradiol and Levothyroxine and liothyronine interaction
Ethynodiol diacetate and ethinyl estradiol and Levothyroxine and liothyronine: 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 and liothyronine (NP Thyroid 60) label · effective 2026-01-01
Estrogen, Oral Contraceptives — Estrogens tend to increase serum thyroxine-binding globulin (TBg).
In a patient with a nonfunctioning thyroid gland who is receiving thyroid replacement therapy, free levothyroxine may be decreased when estrogens are started thus increasing thyroid requirements.
Therefore, patients without a functioning thyroid gland who are on thyroid replacement therapy may need to increase their thyroid dose if estrogens or estrogen-containing oral contraceptives are given.
From the Ethynodiol diacetate and ethinyl estradiol (Kelnor 1/35) label · effective 2023-02-04
…and blood components may be affected by oral contraceptives: a) Increased prothrombin and factors VII, VIII, IX and X; decreased antithrombin III; increased platelet aggregability. b) Increased thyroid binding globulin (TBG), leading to increased circulating total thyroid hormone as measured by protein-bound iodine (PBI), T 4 by column or by radioimmunoassay.
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.