Leflunomide and Methotrexate: Drug Interaction Guide

Quick answer: This is a major interaction — avoid combining Leflunomide and Methotrexate unless specifically directed by your doctor.

Interaction severity: Major — avoid combination

How Leflunomide interacts with Methotrexate

Both drugs are immunosuppressive disease-modifying antirheumatic agents with overlapping hepatotoxic and myelosuppressive effects. Additive toxicity can cause liver injury and bone marrow suppression.

What you should do

Avoid unless specialist-supervised. Monitor liver enzymes, full blood count, and infection risk closely if combination therapy is used.

Key facts

Severity

Major — avoid combination

Mechanism

Both drugs are immunosuppressive disease-modifying antirheumatic agents with overlapping hepatotoxic and myelosuppressiv...

Action

Avoid unless specialist-supervised. Monitor liver enzymes, full blood count, and infection risk closely if combination t...

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 Leflunomide and Methotrexate together?

No — this combination should generally be avoided. Avoid unless specialist-supervised. Monitor liver enzymes, full blood count, and infection risk closely if combination therapy is used.

What is the severity of this interaction?

The interaction between Leflunomide and Methotrexate is classified as Major — avoid combination. Both drugs are immunosuppressive disease-modifying antirheumatic agents with overlapping hepatotoxic and myelosuppressive effects. Additive toxicity can cause liver injury and bone marrow suppression.

What should I do if I'm prescribed both?

Avoid unless specialist-supervised. Monitor liver enzymes, full blood count, and infection risk closely if combination therapy is used. Always consult your prescribing clinician — do not stop or change medications without medical guidance.

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