What is Sulfasalazine?

Sulfasalazine is a medication that is classed as a DMARD- a disease modifying anti-rheumatic drug. This means it acts on the disease itself to reduce the effects of the immune system.

The immune system causes inflammation that protects the body from infections and injury. In certain diseases however, the immune system is over active and this can target healthy tissues such as joints. This results in pain, swelling and tenderness and eventually permanent damage.

Sulfasalazine works to suppress the over activity of the immune system and prevent the inflammation from occurring, reducing the long-term risk of permanent joint damage.


What is Sulfasalazine used for?

Sulfasalazine is used in a number of conditions that cause arthritis, such as rheumatoid arthritis and psoriatic arthritis. It can be used alone or in combination with another DMARD.


How is it taken?

Sulfasalazine is taken daily as a tablet that can be in divided doses. The tablets need to be taken whole, with or without food. They are coated in a special coating so that they dissolve slowly in your stomach. Each tablet is 500mg.

It can take up to 12 weeks for the medication to have its full effect. It is a long-term treatment as it prevents any long-term damage.


When you are starting on sulfasalazine, you are started on a low dose, which is increased weekly up to a maximum of 3000mg (3g) daily, although the maximum dose is dependent on your weight.

The rheumatology department in the hospital will provide the first 8 weeks of tablets and they should be increased as below:


Week Morning Lunch Evening
1 500mg    
2 500mg   500mg
3 500mg 500mg 500mg
4 500mg 500mg 1000mg
5 1000mg 500mg 1000mg
6 1000mg 1000mg 1000mg


As sulfasalazine can affect the blood counts, liver and kidneys, you will need blood monitoring carried out both before and whilst taking the medication. Blood tests are needed at 2 weeks, 4 weeks, 6 weeks and once a month for the first 3 months. After this bloods should be taken every 3 months whilst you are taking sulfasalazine. The rheumatology nurse specialists carry out the first 8 weeks of blood monitoring. They will phone you at 6-8 weeks to see how you are getting along. After 8 weeks the prescription and monitoring will be taken over by your GP.


Side effects 

Some people can experience side effects when taking sulfasalazine, the most common side effects are listed below:



As the immune system is targeted by the sulfasalazine, it is important to get your blood tests checked. Should you develop signs of infection, stop taking your sulfasalazine and speak to your GP as you may require antibiotics. Once you are feeling better and have completed any antibiotics you can restart taking your sulfasalazine.


Sulfasalazine can also affect the blood cell counts, liver and kidneys. If you notice any yellow discoloration to your skin or eyes, bruising and bleeding you should let your doctor know.


If you develop, or come into contact with anyone with shingles or chickenpox, you should speak to your doctor as you may need treatment and to stop taking your sulfasalazine temporarily.


Cautions of use

Interactions with other medications

Contraindications with other conditions


During pregnancy or breastfeeding




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