MedicinePOMEssential

Sulfasalazine

An anti-inflammatory medicine for inflammatory bowel disease and rheumatoid arthritis.

Clinical information

Common uses

ulcerative colitis and Crohn's disease
other inflammatory bowel disease
rheumatoid arthritis

Common side effects

indigestion and heartburn
feeling or being sick
diarrhoea
headache, joint aches
orange-coloured pee (can stain soft contact lenses)

Cautions

regular blood, liver and kidney tests needed
not suitable with sulfonamide, aspirin or salicylate allergy
caution with G6PD deficiency or porphyria
drink plenty of fluids to protect the kidneys

Interactions

digoxin (heart medicine)
diabetes medicines such as metformin or glibenclamide
methenamine (urine infection antibiotic)
folic acid — absorbed less well
azathioprine or mercaptopurine
methotrexate

Pregnancy: no concerns of harm — take high-dose folic acid

Reference information, not medical advice — always follow your doctor or pharmacist. Source: NHS Medicines A–Z, nhs.uk/medicines/sulfasalazine (accessed 2026-08-16)

Approved brands & formulations3

Brand name	Dosage form	Strength	Importer	Category
Sazo EN 500	Tablet ( Enteric coated )	500 mg	—	POM
Sulfsalazine	Tablet	1000mg	—	POM
Sulfsalazine	Tablet	500 mg	—	POM