Adverse reactions to sulfasalazine: the British experience.

Sulfasalazine has been used for a decade in the United Kingdom for treating rheumatoid arthritis. There is now considerable experience with its adverse reaction profile and the incidence of serious events. In the initial weeks of treatment minor side effects are common, especially upper gastrointestinal problems and nausea. Therapy is thus usually introduced slowly and enteric coated tablets are preferred. In 20-30% of patients treatment is discontinued due to an adverse reaction. Most of such reactions occur within 3 months of starting therapy, are trivial, and are self-limiting after withdrawal of the drug. Potentially more serious adverse reactions include leukopenia, rash, abnormal liver function tests, and dyspnea. These reactions also reverse after treatment is stopped. Side effects leading to drug withdrawal after 1 year of therapy are unusual.