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Drink plenty of water with sulfasalazine.

Sulfasalazine can have a number of side-effects, many of which are minor. Some side-effects you should let your doctor know about straightaway - these include any unexplained bleeding, bruising, itchy skin rash, difficulties breathing, sore throat, fever, jaundice, or if you feel generally very unwell.

Sulfasalazine can give some body fluids (such as tears and urine) a yellow/orange colour. This is harmless.

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About sulfasalazine

Type of medicine

An aminosalicylate

Used for

Ulcerative colitis; Crohn's disease; rheumatoid arthritis

Also called


Available as

Tablets, gastro-resistant tablets (these are specially coated to release sulfasalazine in your bowel), oral liquid medicine and suppositories

Sulfasalazine has an anti-inflammatory effect. Although it is not clear exactly how it works, it is thought to block the way inflammation develops in your body.

Sulfasalazine is used to manage the symptoms of inflammatory bowel diseases such as ulcerative colitis and Crohn's disease. Both of these can cause inflammation in the large intestine, leading to problems such as tummy (abdominal) pain and diarrhoea. Sulfasalazine can help control these symptoms.

Sulfasalazine is also prescribed for people with rheumatoid arthritis. It helps to reduce damage to the joints.

Before taking sulfasalazine

Some medicines are not suitable for people with certain conditions, and sometimes a medicine can only be used if extra care is taken. For these reasons, before you start taking sulfasalazine it is important that your doctor knows:

  • If you are pregnant, trying for a baby or breastfeeding.

  • If you have ever had an allergy.

  • If you have asthma.

  • If you have any problems with the way your liver works, or if you have any problems with the way your kidneys work.

  • If you have ever had an allergic reaction to a medicine. It is particularly important that you tell your doctor if you have had an unusual reaction to aspirin, a salicylate, or a sulfonamide. (Sulfonamide is contained in some diuretics and antibiotic medicines.)

  • If you have been told you have an enzyme deficiency called G6PD deficiency, or a blood disorder called porphyria. These are both rare inherited conditions.

  • If you are taking or using any other medicines. This includes any medicines you are taking which are available to buy without a prescription, as well as herbal and complementary medicines.

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How to take sulfasalazine

  • Before you start the treatment, read the manufacturer's printed information leaflet from inside the pack. It will give you more information about sulfasalazine, and it will also provide you with a full list of the side-effects which you could experience.

  • Your dose will depend upon the reason why you have been prescribed sulfasalazine. Your doctor will tell you how much to take and when to take it, and these directions will also be printed on the label of the pack to remind you about what the doctor said to you. As a guide, adults taking sulfasalazine tablets or liquid medicine for an inflammatory bowel problem are likely to be prescribed 500 mg-2 g (1-4 tablets) four times daily. Doses in children are dependent on their body weight. If you are prescribed suppositories, you will be asked to use either one or two suppositories, each morning and evening until your symptoms improve. If you are taking sulfasalazine tablets for rheumatoid arthritis, you will be prescribed 500 mg (1 tablet) daily to begin with, and this will then be increased each week up to a maximum of 6 tablets daily, if needed.

  • Gastro-resistant tablets (these often have 'EN' or 'EC' after the brand name) must be swallowed whole. Do not break, chew or crush the tablets to take them. This is because they are specially coated to pass through your stomach before they are absorbed. Also, do not take any indigestion remedies within two hours of taking your doses (either before or after), as this will interfere with the special coating.

  • You can take sulfasalazine either before or after meals.

  • It is important that you drink plenty of water while you are taking sulfasalazine. This is to avoid any problems with the way your kidneys work.

  • If you forget to take a dose, don't worry, but do remember to take your next dose when it is due. Do not take two doses together to make up for a missed dose.

How to use sulfasalazine suppositories

  1. Empty your bowel, if possible.

  2. Remove the suppository from the packaging.

  3. Using your finger, gently push the suppository into your back passage (rectum). Some people find it helps to squat, or to lie down on one side and draw their knees up towards their chest to do this.

  4. Push the suppository in as far as is comfortable. You may have the urge to pass the suppository out again, but this should ease after a few minutes.

  5. Wash your hands.

Getting the most from your treatment

  • Try to keep your regular appointments with your doctor and clinic. This is so your doctor can check on your progress. Your doctor will want you to have regular blood tests during the treatment.

  • You may notice a difference to the colour of your urine. Sulfasalazine can colour your urine a yellow/orange colour. It is completely harmless and nothing to worry about.

  • If you usually wear soft contact lenses, speak with your optician about this, as sulfasalazine can stain some lenses a yellow/orange colour. You may be advised not to wear certain types of lenses.

  • Treatment with sulfasalazine is often long-term (unless you experience an adverse effect). Continue to take it unless you are advised otherwise by your doctor.

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Can sulfasalazine cause problems?

Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. The table below contains the most common ones associated with sulfasalazine. You will find a full list in the manufacturer's information leaflet supplied with your medicine. The unwanted effects often improve as your body adjusts to the new medicine, but speak with your doctor or pharmacist if any of the following continue or become troublesome.

Very common sulfasalazine side-effects (these affect more than 1 in 10 people)

What can I do if I experience this?

Feeling sick (nausea), loss of appetite

Stick to simple foods - avoid rich or spicy meals

Common sulfasalazine side-effects (these affect fewer than 1 in 10 people)

What can I do if I experience this?

Diarrhoea, tummy (abdominal) pain

Drink plenty of water

Headache, other aches and pains

Drink plenty of water and ask your pharmacist to recommend a suitable painkiller. If the aches continue, let your doctor know

Itchy rash

This may be an allergic type of reaction. Speak with your doctor straightaway if it is severe or affects your whole body

Feeling dizzy

Sit down for a while until the feeling passes. If affected, do not drive and do not use tools or machines until you feel better

Cough, difficulty sleeping, ringing noise in your ears, sore mouth, changes in the way things taste

Speak with your doctor if any of these become troublesome

Important: sometimes, sulfasalazine can cause allergic problems, problems with the blood, and problems with the way the liver works. You should contact your doctor immediately if you develop any of the following:

  • Any difficulties with your breathing, or any swelling of your face or tongue.

  • Any unexplained bleeding, bruising, red or purple discolourations of your skin, or a persistent sore throat, a high temperature (fever), or if you feel generally very unwell.

  • Any yellowing of your skin or the whites of your eyes (jaundice).

How to store sulfasalazine

  • Keep all medicines out of the reach and sight of children.

  • Store in a cool, dry place, away from direct heat and light.

Important information about all medicines

Important information about all medicines

If you buy any medicines check with a pharmacist that they are safe to take with your other medicines.

Never take more than the prescribed dose. If you suspect that you or someone else might have taken an overdose of this medicine go to the accident and emergency department of your local hospital at once. Take the container with you, even if it is empty.

If you are having an operation or dental treatment, tell the person carrying out the treatment which medicines you are taking.

This medicine is for you. Never give it to other people even if their condition appears to be the same as yours.

Do not keep out-of-date or unwanted medicines. Take them to your local pharmacy which will dispose of them for you.

If you have any questions about this medicine ask your pharmacist.

Report side effects to a medicine or vaccine

If you experience side effects, you can report them online through the Yellow Card website.

Further reading and references

Article history

The information on this page is written and peer reviewed by qualified clinicians.

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