Levothyroxine and Magnesium Oxide: Drug Interaction Guide

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

Interaction severity: Moderate — caution required

How Levothyroxine interacts with Magnesium Oxide

Magnesium can adsorb or complex with levothyroxine in the gastrointestinal tract, reducing thyroid hormone absorption and potentially increasing TSH.

What you should do

Separate administration by at least four hours. Recheck TSH after sustained combined use or after the magnesium product is started or stopped.

Key facts

Severity

Moderate — caution required

Mechanism

Magnesium can adsorb or complex with levothyroxine in the gastrointestinal tract, reducing thyroid hormone absorption an...

Action

Separate administration by at least four hours. Recheck TSH after sustained combined use or after the magnesium product ...

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 Magnesium Oxide together?

With caution. Separate administration by at least four hours. Recheck TSH after sustained combined use or after the magnesium product is started or stopped.

What is the severity of this interaction?

The interaction between Levothyroxine and Magnesium Oxide is classified as Moderate — caution required. Magnesium can adsorb or complex with levothyroxine in the gastrointestinal tract, reducing thyroid hormone absorption and potentially increasing TSH.

What should I do if I'm prescribed both?

Separate administration by at least four hours. Recheck TSH after sustained combined use or after the magnesium product 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.