Snapshot A 25-year-old man with a history of ulcerative colitis presents to his gastroenterologist. His ulcerative colitis had been calm but recently he developed rectal bleeding and increasingly frequent stools. A colonoscopy shows diffuse inflammatory changes localized to the rectum. He is started on topical mesalazine as well as oral sulfasalazine, which contains both an anti-inflammatory and anti-bacterial component. Introduction Drugs sulfasalazine Mechanism of action activated by gut bacteria and metabolized into sulfapyridine and 5-aminosalicylic acid (5-ASA) 5-ASA anti-inflammatory (COX inhibitor) inhibits leukotriene synthesis and lipoxygenase sulfapyridine anti-bacterial Clinical use inflammatory bowel disease ulcerative colitis Crohn disease juvenile rheumatoid arthritis Adverse effects gastrointestinal upset drug rash hemolytic anemia in those with G6PD deficiency malaise reversible oligospermia contraindications allergy to sulfa medicines porphyria