Evaluation of Weight-Based Co-trimoxazole Dosing in a Saudi Tertiary Hospital.

Background: Infections caused by  ()and ( pneumonia (PJP)) require weight-based dosing for co-trimoxazole. The aim of this study is to assess the appropriateness of co-trimoxazole dosing in adult inpatients for the treatment of these infections.

Methodology: This is a single-center, cross-sectional study that included adult inpatients treated with co-trimoxazole for a weight-based dose indication ( and PJP). The primary outcome was the appropriateness of co-trimoxazole dosing for these infections.

Results: Forty-three patients were included in the study. Of the 43 patients, 29 (67.4%) were using co-trimoxazole for PJP treatment, and 14 (32.6%) were using it for treatment. The co-trimoxazole dose was appropriate in 22 (51.2%) patients, 21 (72.4%) in the PJP treatment group, and one (7.1%) in the treatment group. Underdosing was observed in 21 (48.8%) patients, of whom eight (27.6%) were in the PJP treatment group and 13 (92.9%) were in the treatment group.

Conclusions: This study found a relatively high rate of underdosing of co-trimoxazole based on weight in hospitalized adults with PJP and infections.