Sulfasalazine is a prescription medication used to treat rheumatoid arthritis and inflammatory bowel diseases such as ulcerative colitis and Crohn’s disease. It is commonly sold under the brand name Azulfidine.
Common side effects include stomach upset, nausea, vomiting, diarrhea, headache, dizziness, and drowsiness. Some people also have difficulty sleeping during the first few days of treatment. Sulfasalazine can turn the urine or tears a yellow-orange or brownish-orange color, which is harmless. Increased sensitivity to sunlight is also common, so wearing sunscreen and protective clothing is recommended.
Although uncommon, sulfasalazine can cause serious side effects. Contact your healthcare provider immediately if you develop a skin rash, blisters, persistent fever, sore throat, unusual fatigue, dark urine, abdominal pain, or yellowing of the skin or eyes (jaundice). Rare but potentially life-threatening reactions include severe skin reactions such as Stevens-Johnson syndrome, liver injury, and serious blood disorders, including agranulocytosis and aplastic anemia.
Because sulfasalazine can affect the liver and blood cells, your healthcare provider may recommend periodic blood tests to monitor for side effects, especially during the first few months of treatment.
