Twice weekly prophylaxis with trimethoprim/sulfamethoxazole for pneumonia in pediatric oncology patients.

Current recommendations for prophylaxis of pneumonia in oncology patients include administration of trimethoprim/sulfamethoxazole (TMP/SMX) three times weekly or the same total weekly dose given daily. The primary objective of this study was to evaluate the efficacy of two consecutive days per week of TMP/SMX for prevention of pneumonia (PJP) in pediatric oncology patients. A retrospective cohort, single-center analysis was conducted in oncology patients 21 years and younger who received TMP/SMX for PJP prophylaxis between February 1, 2013 and July 31, 2017. Changes to the prophylaxis regimen were documented and analyzed. A total of 322 patients received TMP/SMX on two consecutive days per week for PJP prevention, of whom four had confirmed PJP (1.3%). Neutropenia was the most common reason for switching to alternative prophylaxis therapy (11.5%). Two consecutive prophylaxis days with TMP/SMX may be insufficient to prevent PJP in children with hematologic malignancies. Neutropenia remains a barrier for TMP/SMX use for PJP prophylaxis. Further studies to compare PJP incidence in children receiving alternative prophylaxis regimens should be considered.