Colesevelam and Liothyronine interaction
Colesevelam 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 Colesevelam (COLESEVELAM HYDROCHLORIDE) label · effective 2023-12-28
Concomitant use with colesevelam hydrochloride may decrease the exposure of the following drugs: Drugs with a narrow therapeutic index (e.g., cyclosporine), phenytoin, thyroid hormone replacement therapy, warfarin, oral contraceptives containing ethinyl estradiol and norethindrone, olmesartan medoxomil, and sulfonylureas (glimepiride, glipizide, glyburide).
Thyroid Hormone Replacement Therapy Clinical Impact: In vivo drug interactions studies showed a decrease in exposure of levothyroxine when coadministered with colesevelam hydrochloride [see Clinical Pharmacology (12.3) ].
There have been postmarketing reports of elevated thyroid-stimulating hormone (TSH) in patients receiving thyroid hormone replacement therapy [see Adverse Reactions (6.2) ].
Intervention: Administer thyroid hormone replacement therapy 4 hours prior to colesevelam hydrochloride.
From the Liothyronine (Liothyronine Sodium) label · effective 2026-06-04
Drug or Drug Class Effect Bile Acid Sequestrants -Colesevelam -Cholestyramine -Colestipol Ion Exchange Resins -Kayexalate -Sevelamer Bile acid sequestrants and ion exchange resins are known to decrease thyroid hormones absorption.
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.