Levothyroxine and Mitotane interaction

Levothyroxine and Mitotane: both prescribing labels describe an interaction that usually calls for monitoring, a dose change, or spacing the doses.

Moderate

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

Moderate

…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.

Drug interactionsnames MitotaneView label on DailyMed

From the Mitotane (Lysodren) label · effective 2026-03-03

Minor

In cases of cognitive dysfunction, thyroid function should be evaluated as mitotane may induce hypothyroidism.

Warnings and precautionsby drug classView label on DailyMed

Taking more than these two? Interactions stack. Check your whole list at once; it stays in your browser.

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Not 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.