Leflunomide — NZ Medication Guide
📋 Reviewed by a Registered Pharmacist NZ — This information is for general educational purposes only and does not replace professional medical advice. Always consult your doctor or pharmacist before starting, stopping, or changing any medication.
What is Leflunomide?
Leflunomide is a disease-modifying antirheumatic drug (DMARD) used for rheumatoid arthritis and psoriatic arthritis. This medication is funded by Pharmac under Special Authority for rheumatoid arthritis.
What is Leflunomide Used For?
Used for active rheumatoid arthritis and psoriatic arthritis, alone or combined with methotrexate when monotherapy is insufficient.
How Does Leflunomide Work?
Inhibits dihydroorotate dehydrogenase (DHODH), an enzyme essential for pyrimidine synthesis in rapidly dividing T and B lymphocytes — suppressing the autoimmune inflammatory response.
How to Take Leflunomide
Loading dose of 100 mg daily for 3 days (sometimes omitted), then 10–20 mg once daily. Effects take 4–8 weeks. Regular BP, FBC, and LFT monitoring required.
Common Side Effects of Leflunomide
- Diarrhoea
- Nausea
- Hair thinning (alopecia)
- Skin rash
- Headache
- Elevated blood pressure
- Weight loss
Serious Side Effects — Seek Medical Attention
Contact your doctor or call 111 immediately if you experience any of the following:
- Hepatotoxicity (requires LFT monitoring)
- Interstitial lung disease (rare)
- Bone marrow suppression
- Peripheral neuropathy
- Severe skin reactions
Drug Interactions
Leflunomide may interact with other medicines. Always inform your doctor and pharmacist of all medications you are taking. Key interactions include:
- Methotrexate (hepatotoxicity — monitor LFTs closely)
- Warfarin (enhanced anticoagulant effect)
- NSAIDs
- Cholestyramine (used for washout — critical pre-pregnancy)
New Zealand Prescribing Information
Leflunomide (10 mg and 20 mg tablets) is funded under Special Authority, usually after methotrexate trial. Has a very long half-life (up to 2 years without washout). Women planning pregnancy must complete a cholestyramine washout before conception.
Frequently Asked Questions
Can I get pregnant on leflunomide?
No — leflunomide is teratogenic and absolutely contraindicated in pregnancy. A cholestyramine washout protocol is required before conception, and plasma metabolite levels must be confirmed below safe thresholds.
How long will leflunomide take to work?
Improvement is usually seen within 4–8 weeks, with full benefit at 3–6 months.
⚠️ Disclaimer: This page is for educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your doctor or a qualified health provider. In New Zealand, medication availability and funding may vary — check with Pharmac or your pharmacist for current information.
Reviewed by a Registered Pharmacist NZ
References & Further Information
The following New Zealand and international resources were used to inform this page: