Sounds like 'sull-fuh-SAL-uh-zeen'

Sulfasalazine is used to treat conditions associated with inflammation such as rheumatoid arthritis, ulcerative colitis and Crohn's disease. Find out how to take it safely and the possible side effects. Sulfasalazine is also called Salazopyrin.

Type of medicine Also called
  • Aminosalicylate
  • It belongs to a class of medicines known as disease-modifying antirheumatic drugs (DMARDs)
  • Sulphasalazine
  • Salazopyrin®
  • Salazopyrin EN®

What is sulfasalazine?

Sulfasalazine is used to treat many conditions such as rheumatoid arthritis, ulcerative colitis and Crohn's disease. It works by reducing the inflammation and pain related to these conditions. 

In rheumatoid arthritis, sulfasalazine helps to reduce pain, stiffness and swelling of the joints and reduces damage to the joints. Read more about rheumatoid arthritis. 

In inflammatory bowel diseases, such as ulcerative colitis and Crohn's disease, sulfasalazine helps to reduce symptoms such as fever, stomach pain, diarrhoea (runny poo) and rectal bleeding.

A video describing the use of sulfasalazine for the treatment of arthritis.

(RheumInfo, Canada, 2011)


In Aotearoa New Zealand, sulfasalazine is available as 500 mg tablets. There are two types of tablets – plain and enteric coated. The enteric coated tablets (Salazopyrin EN) are specially coated to release the medicine in your bowel rather than your stomach and may have fewer side effects. 

  • Ulcerative colitis and Crohn's disease: the usual dose of sulfasalazine is 1 tablet 4 times a day. Some people may need a lower dose of 1 tablet twice a day. If you have a ‘flare-up’ your dose may be increased for a short time.
  • Rheumatoid arthritis: the usual dose of sulfasalazine is 2 tablets 2–3 times a day. Your doctor will start you on a low dose (1 tablet once a day) and increase your dose slowly over a few weeks. This is so your body can get used to the medicine and it reduces side effects.

How to take sulfasalazine

  • The dose of sulfasalazine will be different for different people.
  • Timing: Take sulfasalazine at the same times each day, with a full glass of water. Take with or after food. Swallow the tablets whole.
  • Missed dose: If you forget to take your dose, take it as soon as you remember. But, if it is nearly time for your next dose, just take the next dose at the right time. Do not take double the dose.
  • Take regularly: Keep taking sulfasalazine every day. It may take 6–12 weeks before you notice the full benefits.
  • Always take your sulfasalazine exactly as your doctor has told you. The pharmacy label will tell you how much sulfasalazine to take, how often to take it, and any special instructions.

Precautions before starting sulfasalazine

  • Are you pregnant, planning a pregnancy or breastfeeding?
  • Do you have problems with your liver or kidneys?
  • Do you have asthma?
  • Have ever had an allergic reaction to a medicine, especially a sulphur antibiotic?
  • Are you taking any other medicines? This includes any medicines you are taking that you can buy without a prescription, as well as herbal and complementary medicines. Warfarin, digoxin and antacids are just some of the medicines that interact with sulfasalazine.

If you answered yes to any of these questions, it’s important that you tell your doctor or pharmacist before you start sulfasalazine. Sometimes a medicine isn’t suitable for a person with certain conditions or it can only be used with extra care.

Precautions while taking sulfasalazine

You will need regular blood tests while taking sulfasalazine to make sure it isn't causing problems with your liver, kidneys or blood.

What are the side effects of sulfasalazine?

Like all medicines, sulfasalazine can cause side effects, but not everyone gets them. Often side effects improve as your body gets used to the new medicine. You will need to have blood tests to make sure it is not affecting your blood or kidneys.

Side effects What should I do?
  • Nausea (feeling sick) or being sick (vomiting)
  • Tummy pain
  • Diarrhoea (runny poo)
  • Headache
  • Dizziness
  • Fever
  • Cough
  • These are quite common when you first start taking sulfasalazine and usually go away with time.
  • Take sulfasalazine with food.
  • Limit or avoid alcohol.
  • Tell your doctor if these side effects bother you.
  • Headache
  • Dizziness
  • Sit down for a while until you feel better.
  • Tell your doctor if they bother you.
  • Signs of problems with your blood cells such as bruising or bleeding easily, ongoing sore throat, mouth ulcers, dizziness, feeling tired and fever.
  • Tell your doctor immediately or ring Healthline 0800 611 116.
  • Allergic reaction including any skin rashes, itching, blisters, peeling skin, swelling of the face, lips or mouth, or breathing problems
  • Tell your doctor immediately or ring Healthline 0800 611 116.
  • Increased sensitivity to the sun and your skin is more likely to burn
  • Avoid unnecessary sun exposure. When outside, protect your skin by using an oil-free sunscreen (SPF50+). Apply the sunscreen to all areas especially the face, neck and ears. Read more about using sunscreen.
  • Sulfasalazine may make your tears, sweat and pee (urine) an orange-yellow colour – this is harmless
  • Avoid wearing soft contact lenses as they may become stained
For more information on side effects, see the Medsafe consumer information leaflets below. 

Did you know that you can report a medicine side effect to the Centre for Adverse Reactions Monitoring (CARM)? Report a side effect to a product

Learn more

Sulfasalazine NZ Formulary
Salazopyrin Medsafe Consumer Information Sheets, NZ
Salazopyrin EN Medsafe Consumer Information Sheets, NZ
Sulfasalazine  Rheuminfo, Canada


Sulfasalazine NZ Formulary
Salazopyrin Medsafe, NZ
Salazopyrin EN Medsafe, NZ
Inflammatory bowel disease – a focus on Crohn’s disease and ulcerative colitis BPAC, NZ

Credits: Sandra Ponen, Pharmacist. Reviewed By: Maya Patel, MPharm PGDipClinPharm, Auckland Last reviewed: 19 Jan 2022