Sulfasalazine

Background

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 also 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 does it work?

Bacteria in the gut convert sulfasalazine into an active form, which acts to help control the overactive immune system.

The daily dose of sulfasalazine is gradually increased each week, usually for three weeks, until the full daily dose has been achieved.

Sulfasalazine is available in tablet or liquid forms and can be taken on its own or in combination with other medicines. It is commonly used in combination with methotrexate.

Most commonly reported side effects

Like any medication, sulfasalazine can cause side effects. It is important to remember that these are only possible side effects and may not happen. Side effects that do happen are usually seen during the first three to six months of treatment. These include:

• Nausea (feeling sick), vomiting, dizziness, headache, diarrhoea, loss of appetite
• Skin rash, raised temperature, insomnia, itchy skin, tinnitus (ringing in the ears)
• Bruising, sore throat, mouth ulcers, cough
• Effects on blood tests, including the blood cell count, liver function and inflammatory markers (CRP and ESR)

Sulfasalazine with other medicines

• Sulfasalazine can interfere with the absorption of folic acid (one of the B vitamins) from the diet. If methotrexate is taken together with sulfasalazine, you will also need to take folic acid supplements.
• Sulfasalazine can reduce the absorption of digoxin, a medicine used for heart conditions
• Sulfasalazine must not be prescribed if you are allergic or sensitive to aspirin or sulfonamide antibiotics

Your healthcare team can advise you of any known interactions with your medication, so it is important to let them know about all the medicines you are taking, whether they are prescribed or over-the-counter. You should also let them know if you are taking any supplements or herbal medicines as these can also interact with medicines.

If you start taking any new medicines, check with a doctor, nurse or pharmacist that they are safe to take with any medicines you are currently taking.

Sulfasalazine during pregnancy and breastfeeding

Sulfasalazine can be taken throughout pregnancy and is considered safe to use when breastfeeding healthy, full-term babies.

As sulfasalazine can reduce the sperm count in men, this may reduce fertility. However, there is no evidence that conception is enhanced by stopping sulfasalazine prior to conception. If conception is delayed for more than 12 months, stopping sulfasalazine and investigating other causes of infertility should be considered and can be discussed with your GP or specialist team.

Pregnancy information in this is based on British Society for Rheumatology (BSR) guidelines on prescribing medicines 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. UK Guidelines recommend drinking no more than 14 units of alcohol a week. This should be spread over at least three days with several days when you do not drink any alcohol. You might need to avoid alcohol if you are
taking other medicines.

Sulfasalazine and immunisation/vaccination

If you are taking sulfasalazine on its own, it would be safe for you to have any vaccinations, whether they are live or not. This may not be the case if you are taking other medicines in combination with sulfasalazine, so it is important to check that all of your RA medicines are safe with live vaccines. For example, live vaccines are not recommended for people taking methotrexate, leflunomide or biologic medicines, but non-live vaccines can be used safely.

Annual flu vaccine is strongly recommended. It is available in two forms: an injection for adults and a nasal spray for children. The injectable vaccine is not a live vaccine and is generally given to adults. The nasal spray is a live vaccine and is generally given to children. You can have a flu vaccination at your GP surgery or local pharmacy.

Annual ‘Pneumovax’ vaccination (which protects against pneumococcal pneumonia) is not live and is strongly recommended.

Shingles (Herpes zoster) vaccine is recommended for all adults turning
65, those aged 70 to 79 and those aged 50 and over with a severely weakened immune system. The vaccination is given as two doses, two months apart. at your GP surgery. It is available as a live or non-live vaccine.

Covid-19 vaccines and boosters are not live and are generally recommended for people with RA.

Your GP can advise if you are eligible for free flu, Pneumovax, shingles and Covid vaccinations, depending on the medications you are taking and their doses.

Hints and tips

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

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.

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Updated: 01/09/2020

Next review: 01/06/2023