Cholestyramine and Levothyroxine and liothyronine interaction
Cholestyramine 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 Cholestyramine label · effective 2026-06-15
Drug Interactions Cholestyramine for Oral Suspension USP may delay or reduce the absorption of concomitant oral medication such as phenylbutazone, warfarin, thiazide diuretics (acidic), or propranolol (basic), as well as tetracycline, penicillin G, phenobarbital, thyroid and thyroxine preparations, estrogens and progestins, and digitalis.
From the Levothyroxine and liothyronine (NP Thyroid 60) label · effective 2026-01-01
Cholestyramine or Colestipol - Cholestyramine or colestipol binds both T 4 and T 3 in the intestine, thus impairing absorption of these thyroid hormones.
Therefore, four to five hours should elapse between administration of cholestyramine and thyroid hormones.
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.