Dapsone penetrates cerebrospinal fluid during Pneumocystis carinii pneumonia prophylaxis

Dapsone has been proposed as a prophylactic agent for both Pneumocystis carinii pneumonia (PCP) and reactivation cerebral toxoplasmosis. To determine whether dapsone penetrates the central nervous system, cerebrospinal fluid (CSF) and serum samples were drawn from patients taking dapsone for PCP prophylaxis. These samples were quantitatively assayed using high-performance liquid chromatography. Five AIDS patients and one cardiac transplant patient had CSF assayed for dapsone. Only one had evidence of CSF inflammation, resulting from a paraspinal abscess. Doses ranged from 50 mg 3 days/week to 100 mg/day, and levels were 0.30-1.61 mu g/ml, which are in the range of inhibition of Toxoplasma gondii tachyzoites. This is the first report to demonstrate that dapsone enters the CSF, and supports preliminary clinical evidence that dapsone may have protective activity against cerebral toxoplasmosis when used for PCP prophylaxis.