Sulfasalazine

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

Easy-to-read medicine information about sulfasalazine – what it is, how to take sulfasalazine safely and possible side effects.

Type of medicine Also called
  • Aminosalicylate
  • 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. Sulfasalazine does not cure 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 and rectal bleeding.

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

Watch a video about sulfasalazine for the treatment of arthritis.

Dose

  • Ulcerative colitis and Crohn's disease: the usual dose of sulfasalazine is 1 tablet four times a day. Some people may need a lower dose of 1 tablet two times 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 to 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 reduces side effects.
  • 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.

How to take sulfasalazine

  • Take sulfasalazine at the same times each day, with a full glass of water.
  • It is best to take sulfasalazine with or after food.
  • Sulfasalazine EN tablets have a special coating so the tablet can pass through the stomach. The tablet must be swallowed whole. Do not break, chew or crush the tablets. Do not take any indigestion remedies within 2 hours of taking these tablets; this will interfere with the coating.
  • Plain sulfasalazine tablets may be crushed.
  • 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.
  • Keep taking sulfasalazine every day. It may take 6 to 12 weeks before you notice the full benefits.

Other tips

  • Drink plenty of water: it is important that you drink plenty of water while you are taking sulfasalazine (about 6 glasses a day). This is to avoid any problems with your kidneys.
  • Increased sensitivity to the sun: sulfasalazine can make you more sensitive 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.
  • Blood tests: you will need regular blood tests while taking sulfasalazine to check if it is causing problems with your liver, kidneys or blood.
  • Colour changes: 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.

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 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.

If so, 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.

Possible side effects

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 troublesome
  • Headache
  • Dizziness
  • Sit down for a while until you feel better.
  • Tell your doctor if troublesome
  • Signs of problems with your blood cells such as bruising or bleeding easily, ongoing sore throat, mouth ulcers, dizziness and 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, mouth or have problems breathing
  • Tell your doctor immediately or ring HealthLine 0800 611 116

Interactions

Sulfasalazine interacts with many medications and herbal supplements (such as St. John's Wort) so check with your doctor or pharmacist. Do not take any indigestion remedies within two hours (before or after) of taking sulfasalazine.

Learn more

Sulfasalazine New Zealand Formulary

Salazopyrin; Salazopyrin EN Medsafe Consumer Information Sheets

Credits: Sandra Ponen, Pharmacist. Reviewed By: Angela Lambie, Pharmacist, Auckland Last reviewed: 03 Jun 2019