BMA Concise Guide to Medicine & Drugs


Brand names Salazopyrin, Sulazine EC

Used in the following combined preparations None


Drug group Drug for inflammatory bowel disease and disease-modifying antirheumatic drug

Overdose danger rating Low

Dependence rating Low

Prescription needed Yes

Available as generic Yes


Sulfasalazine, a chemical combination of a sulphonamide and a salicylate, is used to treat two inflammatory disorders affecting the bowel: ulcerative colitis (which mainly affects the large intestine), and Crohn’s disease (which usually affects the small intestine). Sulfasalazine is also used to modify, halt, or slow the underlying disease process in severe rheumatoid arthritis.

Adverse effects such as nausea, loss of appetite, and general discomfort are more likely when higher doses are taken. Side effects caused by stomach irritation may be avoided by changing to a specially coated tablet form of the drug. Allergic reactions such as fever and skin rash may be avoided or minimized by low initial doses of the drug, followed by gradual increases. Maintenance of adequate fluid intake is important while taking this drug. In rare cases among men, temporary sterility may occur.


Your drug prescription is tailored for you. Do not alter dosage without checking with your doctor.

How taken/used Tablets, liquid, suppositories.

Frequency and timing of doses 2–4 x daily after meals with a glass of water (tablets); 2 x daily (suppositories).

Adult dosage range 4–8g daily in acute attacks; up to 2g daily for maintenance therapy (Crohn’s disease/ulcerative colitis). 500mg–3g daily (rheumatoid arthritis).

Onset of effect Adverse effects may occur within a few days, but full beneficial effects may take 1–3 weeks, depending on the severity of the condition.

Duration of action Up to 24 hours.

Diet advice It is important to drink plenty of liquids (at least 1.5 litres a day) during treatment. Sulfasalazine may reduce the absorption of folic acid from the intestine, leading to a deficiency of this vitamin. Eat plenty of green vegetables.

Storage Keep in original container at room temperature out of the reach of children.

Missed dose Take as soon as you remember. If your next dose is due within 2 hours, take a single dose now and skip the next.

Stopping the drug Do not stop the drug without consulting your doctor; symptoms may recur.

Exceeding the dose An occasional unintentional extra dose is unlikely to be a cause for concern. But if you notice any unusual symptoms, or if a large overdose has been taken, notify your doctor.


Adverse effects are common with sulfasalazine but may disappear with a reduction in dosage. Symptoms such as nausea and vomiting may be helped by taking the drug with food. Orange or yellow discoloration of the urine may occur but is no cause for concern. Other common side effects include malaise, loss of appetite, headache, and joint pain; discuss with your doctor if headache or joint pain occur or if the other symptoms are severe. Ringing in the ears is rare; discuss with your doctor if it is severe. Fever, a rash, and unusual bruising or bleeding are also rare side effects of sulfasalazine; seek immediate medical attention if they occur.


General note 1 Sulfasalazine may increase the effects of some drugs, including mercaptopurine and azathioprine.

General note 2 Sulfasalazine reduces the absorption and effect of some drugs, including digoxin, folic acid, and iron.


Be sure to tell your doctor if:

· You have long-term liver or kidney problems.

· You have glucose-6-phosphate dehydrogenase (G6PD) deficiency.

· You have a blood disorder.

· You suffer from porphyria.

· You are allergic to sulphonamides or salicylates.

· You wear soft contact lenses.

· You are taking other medicines.

Pregnancy No evidence of risk to developing fetus. Folic acid supplements may be required. Discuss with your doctor.

Breast-feeding The drug passes into the breast milk and may affect the baby. Discuss with your doctor.

Infants and children Not recommended under 2 years. Reduced dose necessary for older children, according to body weight.

Over 60 No special problems.

Driving and hazardous work No special problems.

Alcohol No known problems.


Blood disorders may occur with prolonged use of this drug. Maintenance dosage is usually continued indefinitely.

Monitoring Periodic tests of blood composition and liver function are usually required.