Adverse reaction profile of sulfasalazine and its persistence in chronic therapy of rheumatoid arthritis and spondyloarthritis: A multicentric observational study

Objectives: Sulfasalazine has been widely used in treatment of rheumatoid arthritis and spondyloarthritis. This study aims to assess persistence with sulfasalazine and also frequency and severity of adverse drug reactions (ADRs) encountered with this very well-established disease-modifying anti-rheumatoid drug. Materials and methods: This retrospective study was done in 1,114 patients from medicine and rheumatology outpatient departments of six centers across India. The inclusion criteria was patients taking sulfasalazine. Patients receiving sulfasalazine for rheumatoid arthritis or spondyloarthritis were selected and details on drugs used, duration of taking sulfasalazine, ADRs to sulfasalazine and whether sulfasalazine had to be stopped due to ADRs were analyzed. Results: Of the total of patients included in the study, 10.1% had ADRs with sulfasalazine, and stopped the drug. Gastritis, deranged liver enzymes, hepatitis, skin rashes were the most commonly encountered ADRs. Of the total number of patients recruited for the study, 11% were lost to follow-up, as most of the centers were army hospitals and the officers and staff were posted to other places. Sulfasalazine was taken for less than 1 month by 3.8% patients while 12.5% had taken the drug for less than 6 months. Of the study patients, 28.6% had taken the drug for 24 - 60 months and 4.6% (51 patients) had taken it for more than 5 years. It was found that ADRs were most commonly encountered within the first year of using the drug, and persistence was seen in patients on long-term therapy. Conclusion: Sulfasalazine is a safe option in chronic therapy of rheumatoid arthritis and spondyloarthritis. Although frequency of ADRs with patients taking sulfasalazine is minimal, it did necessitate the stoppage of drug. If not well tolerated, sulfasalazine would not have been continued for more than 12 months as evidenced from this study.