Cholestyramine and Levothyroxine: Drug Interaction Guide

Quick answer: This combination requires caution. Cholestyramine and Levothyroxine can be used together with adjustments and monitoring.

Interaction severity: Moderate — caution required

How Cholestyramine interacts with Levothyroxine

Cholestyramine binds levothyroxine in the gut lumen, reducing its absorption by up to 50% and causing reappearance of hypothyroid symptoms.

What you should do

Separate doses by at least 4 hours and monitor TSH 6-8 weeks after either drug is started or stopped.

Key facts

Severity

Moderate — caution required

Mechanism

Cholestyramine binds levothyroxine in the gut lumen, reducing its absorption by up to 50% and causing reappearance of hy...

Action

Separate doses by at least 4 hours and monitor TSH 6-8 weeks after either drug is started or stopped.

Important medical disclaimer: This page provides educational information about drug interactions for general reference. It is not a substitute for professional medical advice, diagnosis, or treatment. Always discuss your specific medications with a qualified healthcare provider before starting, stopping, or changing any treatment. About our editorial team.

Frequently asked questions

Can I take Cholestyramine and Levothyroxine together?

With caution. Separate doses by at least 4 hours and monitor TSH 6-8 weeks after either drug is started or stopped.

What is the severity of this interaction?

The interaction between Cholestyramine and Levothyroxine is classified as Moderate — caution required. Cholestyramine binds levothyroxine in the gut lumen, reducing its absorption by up to 50% and causing reappearance of hypothyroid symptoms.

What should I do if I'm prescribed both?

Separate doses by at least 4 hours and monitor TSH 6-8 weeks after either drug is started or stopped. Always consult your prescribing clinician — do not stop or change medications without medical guidance.

Last reviewed: by iMedic Medical Editorial Team. Our editorial process.