Levothyroxine and Propranolol: Drug Interaction Guide

Quick answer: Levothyroxine and Propranolol have a minor interaction — typically manageable with awareness.

Interaction severity: Minor — typically manageable

How Levothyroxine interacts with Propranolol

At higher doses, propranolol inhibits type 1 iodothyronine deiodinase and reduces peripheral conversion of thyroxine to triiodothyronine.

What you should do

No routine adjustment is usually required for stable replacement therapy. Interpret thyroid tests and clinical response carefully after major propranolol dose changes.

Key facts

Severity

Minor — typically manageable

Mechanism

At higher doses, propranolol inhibits type 1 iodothyronine deiodinase and reduces peripheral conversion of thyroxine to ...

Action

No routine adjustment is usually required for stable replacement therapy. Interpret thyroid tests and clinical response ...

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 Levothyroxine and Propranolol together?

Usually yes, with awareness. No routine adjustment is usually required for stable replacement therapy. Interpret thyroid tests and clinical response carefully after major propranolol dose changes.

What is the severity of this interaction?

The interaction between Levothyroxine and Propranolol is classified as Minor — typically manageable. At higher doses, propranolol inhibits type 1 iodothyronine deiodinase and reduces peripheral conversion of thyroxine to triiodothyronine.

What should I do if I'm prescribed both?

No routine adjustment is usually required for stable replacement therapy. Interpret thyroid tests and clinical response carefully after major propranolol dose changes. Always consult your prescribing clinician — do not stop or change medications without medical guidance.

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