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How and when to take sulfasalazine

Always take or use sulfasalazine as a doctor or pharmacist tells you, and follow the instructions on the leaflet in the medicine packet.

Dosage and strength

Sulfasalazine tablets and suppositories contain 500mg of sulfasalazine. The liquid contains 250mg in 5ml.

Your dose and how often you take or use sulfasalazine will depend on why you need it, the type you’re using and how severe your symptoms are.

For inflammatory bowel disease the usual dose at the start of your treatment is either:

  • 2 to 4 tablets or 20ml to 40ml of liquid, 4 times a day
  • 1 to 2 suppositories, twice a day

For rheumatoid arthritis, the usual dose at the start of your treatment is 1 tablet (500mg) taken once a day. This will increase by 1 tablet each week until you reach a dose of 1 tablet 4 times a day (2g a day), or 2 tablets 3 times a day (3g a day), depending on how it works for you.

For children, the dose may be lower. The doctor will usually prescribe a dose based on your child's weight.

Changes to your dose

When your symptoms start to get better, your doctor may reduce your dose. This lower dose, sometimes called a maintenance dose, will help keep your symptoms under control.

If your symptoms get worse again, your doctor may want to increase your dose.

How to take it

Drink plenty of fluids when taking this medicine to help prevent possible kidney problems.

How to take sulfasalazine tablets

Swallow the tablets whole with a drink of water. Do not break, chew or crush them. This is because some tablets have a special coating to protect the medicine from the acids in your stomach.

You can take sulfasalazine tablets with or without food.

Try to space the doses evenly throughout the day and night, with a gap of no more than 8 hours between your bedtime and morning dose.

How to take sulfasalazine liquid

Take the liquid with food.

Try to space the doses evenly throughout the day and night, with a gap of no more than 8 hours between your bedtime and morning dose.

How to use sulfasalazine suppositories

You'll generally use the suppositories twice a day, in the morning and at bedtime. Use them after you do a poo.

  1. Wash your hands before using the suppository. Also clean around your bottom (anus) with mild soap and water, rinse and pat dry.
  2. Unwrap the suppository.
  3. Gently push the suppository into your bottom with the pointed end first. It needs to go in about 3 centimetres (1 inch).
  4. Sit or lie down for about 15 minutes. The suppository will melt inside your bottom. This is normal.
  5. Wash your hands again.
  6. Try not to empty your bowels for at least an hour after inserting the suppository so it will work better.

How long to take it for

If you're having a flare up, your doctor may prescribe you a higher dose of sulfasalazine for a short time.

You can also take it long term to keep inflammation under control and prevent symptoms from flaring up again. How long you use it for will depend on your condition and how severe it is.

Do not stop using sulfasalazine unless your doctor tells you to.

If you forget to take it

If you miss a dose of sulfasalazine, take it as soon as you remember, unless it's nearly time for your next dose. In this case, skip the missed dose and take your next dose at the usual time.

Never take 2 doses at the same time. Never have an extra dose to make up for a forgotten one.

If you often forget doses, it may help to set an alarm to remind you. You could also ask your pharmacist for advice on other ways to help you remember to take your medicine.

If you take too much

Taking up to 1 extra dose of sulfasalazine is unlikely to cause you any problems.

Urgent advice: Contact 111 for advice now if:

  • you've taken or used up to 1 extra dose of sulfasalazine and you feel unwell
  • you've taken or used more than 1 extra dose of sulfasalazine, even if you feel well

Go to 111 online or call 111. Call 111 if you're asking about a child under 5 years old.

Information:

If you need to go to A&E, do not drive. Ask someone to drive you or call 999 and ask for an ambulance.

Bring the sulfasalazine packet or leaflet inside it, any remaining medicine, and any other medicines you take.

Page last reviewed: 5 March 2025
Next review due: 5 March 2028