Sulfasalazine — 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 Sulfasalazine?
Sulfasalazine is a DMARD and anti-inflammatory medicine used for rheumatoid arthritis and inflammatory bowel disease. This medication is funded by Pharmac for rheumatoid arthritis and IBD.
What is Sulfasalazine Used For?
Used for rheumatoid arthritis, ankylosing spondylitis, juvenile idiopathic arthritis, ulcerative colitis, and Crohn’s disease.
How Does Sulfasalazine Work?
Cleaved by gut bacteria into sulfapyridine (anti-inflammatory, immunomodulatory — relevant in arthritis) and 5-aminosalicylic acid (anti-inflammatory in the colon — relevant in IBD).
How to Take Sulfasalazine
Start at 500 mg/day, increase over 4–8 weeks to 2–3 g/day in divided doses. Enteric-coated tablets (Salazopyrin EN-Tabs®) are better tolerated. Take with food and plenty of water.
Common Side Effects of Sulfasalazine
- Nausea (common initially — take with food)
- Headache
- Orange-yellow discolouration of urine (harmless)
- Skin rash
- Reduced sperm count (reversible)
Serious Side Effects — Seek Medical Attention
Contact your doctor or call 111 immediately if you experience any of the following:
- Agranulocytosis (requires FBC monitoring)
- Hepatotoxicity
- Stevens-Johnson syndrome (rare)
- Folate deficiency
- Pulmonary toxicity (rare)
Drug Interactions
Sulfasalazine may interact with other medicines. Always inform your doctor and pharmacist of all medications you are taking. Key interactions include:
- Methotrexate (folate depletion — monitor closely)
- Digoxin (reduced absorption)
- Warfarin (enhanced anticoagulant effect)
New Zealand Prescribing Information
Sulfasalazine (Salazopyrin® 500 mg and Salazopyrin EN-Tabs® 500 mg) is funded by Pharmac. Regular FBC and LFT monitoring is required. Folic acid supplementation (5 mg weekly) is recommended.
Frequently Asked Questions
Will sulfasalazine affect my fertility?
It causes reversible oligospermia in men, which typically reverses within 2–3 months of stopping. Men planning fatherhood should discuss switching with their rheumatologist.
Why is my urine orange on sulfasalazine?
This orange-yellow discolouration is harmless and caused by the medicine’s metabolites. Warn your optometrist if you wear soft contact lenses, as they may become discoloured.
⚠️ 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: