Acute psychosis related to use of trimethoprim/sulfamethoxazole in the treatment of HIV-infected patients with Pneumocystis jirovecii pneumonia: a multicentre, retrospective study.

Objectives: A recent study reported that trimethoprim/sulfamethoxazole caused acute psychosis in four renal transplant patients with Pneumocystis jirovecii pneumonia. We aimed to investigate the incidence of and factors associated with trimethoprim/sulfamethoxazole-related acute psychosis in HIV-infected patients with P. jirovecii pneumonia.

Methods: We reviewed the medical records of HIV-infected patients who presented with P. jirovecii pneumonia and received trimethoprim/sulfamethoxazole at six major hospitals in Taiwan from July 2009 to May 2011. Acute psychosis was defined as the occurrence of hallucinations or delusions following the initiation of trimethoprim/sulfamethoxazole during hospitalization.

Results: During the study period, 135 patients receiving trimethoprim/sulfamethoxazole for P. jirovecii pneumonia were enrolled and 16 (11.9%; 95% CI, 6.3%-17.4%) developed acute psychosis after a median duration of 5 days of trimethoprim/sulfamethoxazole treatment (range, 3-11 days). The incidence increased from 0% (0/16) in patients who received a daily trimethoprim dose of ≤12 mg/kg to 23.5% (4/17) in those who received a daily trimethoprim dose of >18 mg/kg. In multivariate logistic regression analysis, a higher daily dose of trimethoprim/sulfamethoxazole (OR, per 1 mg increase of trimethoprim, 1.40; 95% CI, 1.12-1.76; P = 0.0035) and use of adjunctive steroids (OR, 4.43; 95% CI, 1.14-17.15; P = 0.031) were associated with acute psychosis.

Conclusions: In this case series, 11.9% of HIV-infected patients developed acute psychosis while receiving trimethoprim/sulfamethoxazole for P. jirovecii pneumonia. While the study was limited by its retrospective design, the risk appeared to increase with increasing daily dose of trimethoprim/sulfamethoxazole in those vulnerable patients with multiple risks for acute psychosis.