Ferrous Sulfate and Levothyroxine: Drug Interaction Guide

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

Interaction severity: Moderate — caution required

How Ferrous Sulfate interacts with Levothyroxine

Ferrous sulfate forms insoluble chelation complexes with levothyroxine in the gut, reducing its absorption and lowering circulating thyroxine levels.

What you should do

Separate administration by at least 4 hours. Monitor TSH 6-8 weeks after initiation or discontinuation of iron therapy.

Key facts

Severity

Moderate — caution required

Mechanism

Ferrous sulfate forms insoluble chelation complexes with levothyroxine in the gut, reducing its absorption and lowering ...

Action

Separate administration by at least 4 hours. Monitor TSH 6-8 weeks after initiation or discontinuation of iron therapy.

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 Ferrous Sulfate and Levothyroxine together?

With caution. Separate administration by at least 4 hours. Monitor TSH 6-8 weeks after initiation or discontinuation of iron therapy.

What is the severity of this interaction?

The interaction between Ferrous Sulfate and Levothyroxine is classified as Moderate — caution required. Ferrous sulfate forms insoluble chelation complexes with levothyroxine in the gut, reducing its absorption and lowering circulating thyroxine levels.

What should I do if I'm prescribed both?

Separate administration by at least 4 hours. Monitor TSH 6-8 weeks after initiation or discontinuation of iron therapy. Always consult your prescribing clinician — do not stop or change medications without medical guidance.

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