Objective. For reasons of insufficient quality of the raw material, aurothioglucose was withdrawn from the Dutch market at the end of 2001. Aurothiomalate became available as an alternative preparation. We followed a cohort of patients during the first year after switching from aurothioglucose to aurothiomalate to study efficacy and tolerability.Methods. Patients were observed at baseline and at 3 and 12 months after switching. At each visit, data on adverse drug reactions (ADR), withdrawal, and disease activity were collected.Results. In total 120 patients were included [age 63 (SD 15) yrs, 68% female, 93% with rheumatoid arthritis, duration of disease 15 (SD 9) years, 82% I-M rheumatoid factor-positive, with 9 (SD 9, range 0.1-45) yrs of previous aurothioglucose therapy]. Nineteen patients (16%) reported an ADR taking aurothiomalate not previously experienced with aurothioglucose, the most frequently reported being pruritus, dermatitis/stomatitis, and chrysiasis/hyperpigmentation. Twenty-nine patients (24%) withdrew from aurothiomalate within 12 months of followup for reasons of inefficacy (14%), ADR (7%), or disease in state of remission (3%). Kaplan-Meier estimates show aurothiomalate survival rates of 78.5% after 12 months. No statistically significant differences between the disease activity indicators during followup visits compared with the baseline visit were detected for the patients continuing aurothiomalate.Conclusion. Within the first 12 months after switching from aurothioglucose, 24% of patients withdrew from aurothiomalate. Sixteen percent of patients reported novel ADR. For the population continuing to take aurothiomalate no clinically relevant changes in disease activity were recorded after switching.