Sulfasalazine was introduced in the 1950s, initially to treat inflammatory bowel disease, but also for the treatment of RA. It remains a common RA treatment.  


Sulfasalazine is known as a disease modifying anti-rheumatic drug (DMARD).

In the gut sulfasalazine is broken down (by the normal gut bacteria) into two parts: one part a sulphonamide antibiotic which kills harmful bacteria; and a second part which acts to reduce the process driving inflammation as well as helping to control the overactive immune system.

This overactive immune system in RA is the cause of swelling, pain, heat and redness in the joints and other associated symptoms such as fatigue and generally feeling unwell.

Sulfasalazine may be prescribed as a single DMARD or prescribed at the same time as another DMARD. It is frequently prescribed in combination with methotrexate.


  • Sulfasalazine was introduced in the 1950s, initially to treat inflammatory bowel disease, but also for the treatment of rheumatoid arthritis (RA) as it was believed then that bacterial infections were the cause of this form of arthritis
  • Following positive results from clinical trials in the late 1970s it was used more extensively in RA and subsequently used for some forms of juvenile arthritis (but not extensively)
  • Sulfasalazine is also used to treat inflammatory bowel disease, ulcerative colitis and Crohn’s disease

How long does it take to work?  

  •  Sulfasalazine is available in liquid form or tablets
  • The daily dose of sulfasalazine is gradually increased each week, usually for three weeks, until the maximum prescribed daily dose has been achieved
  • Controlling the symptoms of RA with sulfasalazine may take up to three months or longer

Most commonly reported side effects  

Most commonly reported side effects As with any medication, sulfasalazine has a number of possible side effects although it is important to remember that these are only potential side effects and may not occur. Side effects that can occur will be experienced during the first three to six months. These include:

  • Nausea (feeling sick), vomiting, dizziness, headache, diarrhoea, loss of appetite
  • Skin rash, raised temperature, insomnia, itching of skin, tinnitus
  • Bruising, sore throat, mouth ulcers, cough
  • Effects on the blood tests, including the blood cell count, the blood chemistry and liver tests and measures of inflammation (using tests known as ESR and CRP)
  • Yellow/orange discoloration of the urine, protein in urine (proteinuria)
  • For young men, reduced sperm count whilst on the drug, reversible on stopping

More information on side effects can be found in the patient information leaflet for sulfasalazine 

Remember to report any concerns about possible side effects to the doctors or nurses.  

 Sulfasalazine with other medicines  

  • Sulfasalazine may interfere with the absorption of folic acid (one of the B vitamins) from the diet. If methotrexate is prescribed as well as sulfasalazine the regimen for a weekly supplement of folic acid will be required — Sulfasalazine may reduce the absorption of some heart drugs
  • Sulfasalazine must not be prescribed if you are sensitive to sulphonamides or aspirin
  • If you are taking sulfasalazine, do not buy any other medicine or remedy (eg for colds or flu) without first consulting your doctor, nurse or pharmacist
  • Remember to take care when using any other medications or complementary therapies (even if bought ‘over the counter’ for colds or flu). Remember to check with a doctor, nurse or pharmacist that they are safe to take with sulfasalazine and any other medication taken

Sulfasalazine during pregnancy and breastfeeding  

  • Sulfasalazine can be prescribed to take throughout all stages of pregnancy and is compatible with breastfeeding in healthy, full-term infants.
  • Men taking sulfasalazine may have reduced fertility. However, there is no evidence that conception is enhanced by stopping sulfasalazine for 3 months prior to conception unless conception is delayed for more than 12 months, when other causes of infertility should also be considered.
  • Pregnancy information in this booklet is based on British Society for Rheumatology (BSR) guidelines on prescribing drugs in pregnancy and breastfeeding. Before starting a family it is recommended that you get advice from the consultant or clinical nurse specialist about when to start a pregnancy.

Sulfasalazine and alcohol  

Alcohol can be consumed when taking sulfasalazine. However, caution may be required when taking other medications alongside this drug, for example methotrexate.  

Sulfasalazine and immunisation/vaccination  

If you are taking sulfasalazine, immunisations and vaccinations can be given if required.  

Live vaccines are considered safe to take while on sulfasalazine. However, this may not be the case for other drugs that you may be taking alongside this drug, so it is important to check the safety with all your RA medications and live vaccines. Methotrexate, for example is a drug often used alongside sulfasalazine and live vaccines are not recommended for those taking methotrexate (see p.30 for further details).

Flu vaccine is now available in two forms, an injection for adults (which is not a live vaccine) and a nasal spray for children (which is live). It is important to discuss having a flu vaccination with your GP, as this is generally recommended to people with RA.

Vaccination of close family members can help to protect someone with a lowered immune system from infection.

 Hints and tips  

  • Stay safe on sulfasalazine by remembering to have regular blood test monitoring as advised by the consultant or clinical nurse specialist  
  • Remember that contraception is still required if men taking sulfasalazine do not wish to father a child even though the sperm count is likely to be lowered  

Medicines in rheumatoid arthritis

We believe it is essential that people living with RA understand why certain medicines are used, when they are used and how they work to manage the condition.


Updated: 01/09/2020