Drug interactions
Cholestyramine + Levothyroxine
Severity: Major
Cholestyramine and Levothyroxine: major interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Cholestyramine markedly reduces levothyroxine absorption, which can cause hypothyroidism or loss of TSH suppression in treated patients.
What this interaction means in plain words
Cholestyramine and Levothyroxine can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Cholestyramine belongs to Cardiovascular; Levothyroxine belongs to Endocrine.
Why it happens
Resin binds levothyroxine in the gut and prevents its absorption.
What to do
Separate levothyroxine from cholestyramine by at least 4 hours. Check TSH after starting or stopping the resin and adjust the dose.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Cholestyramine and Levothyroxine, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 14 days on the web. No card needed.
Other interactions of Cholestyramine
Other interactions of Levothyroxine
- Levothyroxine + Sodium iodide i-131 Major
- Levothyroxine + Tiratricol Major
- Adrenaline-articaine + Levothyroxine Moderate
- Alogliptin-metformin + Levothyroxine Moderate
- Amitriptyline + Levothyroxine Moderate
- Amobarbital + Levothyroxine Moderate
Frequently asked questions
Can I take Cholestyramine with Levothyroxine?
MediHelp rates the interaction as major. Cholestyramine and Levothyroxine can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Cholestyramine markedly reduces levothyroxine absorption, which can cause hypothyroidism or loss of TSH suppression in treated patients.
How serious is the interaction between Cholestyramine and Levothyroxine?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Separate levothyroxine from cholestyramine by at least 4 hours. Check TSH after starting or stopping the resin and adjust the dose.
What other medicines interact with Cholestyramine?
MediHelp also lists interactions of Cholestyramine with, for example, Cholic acid, Deferasirox, Leflunomide. The full list is on the Cholestyramine page.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
