Colestyramine and Levothyroxine: Drug Interaction Guide

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

Interaction severity: Moderate — caution required

How Colestyramine interacts with Levothyroxine

Colestyramine binds levothyroxine in the intestine and interrupts its absorption and enterohepatic recycling. This can reduce thyroid hormone exposure and increase TSH.

What you should do

Administer levothyroxine at least four to six hours apart from colestyramine. Monitor TSH and adjust levothyroxine if necessary.

Key facts

Severity

Moderate — caution required

Mechanism

Colestyramine binds levothyroxine in the intestine and interrupts its absorption and enterohepatic recycling. This can r...

Action

Administer levothyroxine at least four to six hours apart from colestyramine. Monitor TSH and adjust levothyroxine if ne...

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 Colestyramine and Levothyroxine together?

With caution. Administer levothyroxine at least four to six hours apart from colestyramine. Monitor TSH and adjust levothyroxine if necessary.

What is the severity of this interaction?

The interaction between Colestyramine and Levothyroxine is classified as Moderate — caution required. Colestyramine binds levothyroxine in the intestine and interrupts its absorption and enterohepatic recycling. This can reduce thyroid hormone exposure and increase TSH.

What should I do if I'm prescribed both?

Administer levothyroxine at least four to six hours apart from colestyramine. Monitor TSH and adjust levothyroxine if necessary. Always consult your prescribing clinician — do not stop or change medications without medical guidance.

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