Reassessing the efficacy and safety of trimethoprim-sulfamethoxazole for Pneumocystis jirovecii pneumonia: a retrospective study.

PURPOSE: The conventional dose of trimethoprim-sulfamethoxazole (TMP-SMX) for treating patients with Pneumocystis jirovecii pneumonia (PCP) has been associated with a higher incidence of adverse events. This study aimed to evaluate the safety and efficacy of conventional and low-dose TMP-SMX regimens in such patients. METHODS: A retrospective study was conducted on patients with non-human immunodeficiency virus (HIV)-associated PCP treated with TMP-SMX from January 2020 to February 2024. Clinical characteristics and treatment outcomes were collected. Patients were divided into conventional-dose (TMP, 15–20 mg/kg/day) and low-dose (TMP, < 15 mg/kg/day) groups. Univariate and multivariable logistic regression analyses were performed. RESULTS: The study included 140 patients, with 68 receiving conventional-dose TMP-SMX (TMP, 15–20 mg/kg/day) and 72 receiving low-dose TMP-SMX (TMP, < 15 mg/kg/day). Non-significant differences were observed in the length of hospital stay (p = 0.834) and 30-day mortality (p = 0.134) between the two groups. The overall adverse events rate was significantly higher in the conventional-dose group (p = 0.027). Acute kidney injury occurred in 15.7% of patients (22/140) and hyperkalemia in 14.3% (20/140) without significant differences between groups. Elevated alanine aminotransferase/aspartate aminotransferase occurred in 16.2% of the conventional-dose group and 2.8% of the low-dose group (p = 0.006). Multivariable logistic regression analysis identified baseline creatinine clearance (p = 0.046) and TMP-SMX daily dose (p = 0.017) as independent risk factors for total adverse events. CONCLUSIONS: Low-dose TMP-SMX for PCP treatment provides satisfactory outcomes with fewer adverse events. Adjusting TMP-SMX dosage may represent a valuable therapeutic optimization strategy.