Izuka S, , Yamashita H, et al. - This study was carried out to assess the prevalence of trimethoprim-sulfamethoxazole (TMP-SMX)-related adverse drug reactions (ADRs) in patients with SLE and distinguish specific risk factors for ADR development in these patients. Data were retrospectively examined from patients with connective tissue disease (CTD) who were administered TMP-SMX as a PCP prophylactic. Researchers compared the prevalence of ADRs between patients with SLE and those with other CTDs. They conducted univariate and multivariate analyses to distinguish risk factors for ADRs in patients with SLE. A total of 424 patients with CTD were included in this study (SLE, n = 162; other CTDs, n = 262), 22 with SLE (13.6%) developed ADRs, and this rate was significantly higher than that observed in patients with non-SLE CTDs (n = 18 [6.9%], p = 0.033). The findings revealed that patients with SLE who are prophylactically administered TMP-SMX are at high risk of ADRs. Those who display a positive anti-Sm antibody should be carefully monitored for ADRs among these patients.