Penetration of dapsone into cerebrospinal fluid of patients with AIDS

It has been proposed that dapsone in combination with pyrimethamine could be used for prophylaxis of both Pneumocystis carinii pneumonia and encephalitis due to Toxoplasma gondii. Ten patients with AIDS undergoing lumbar puncture for diagnostic purposes were studied in order to assess the penetration of dapsone into CSF. Blood and CSF samples were obtained between 3 and 72 h following administration. Six patients had received oral dapsone for at least 1 month at the dosage regimen of 100 mg twice of three times weekly and four patients had received a single oral 100 mg dose. Dapsone concentration in CSF ranged from 0.013 to 0.296 mg/L while concentrations in plasma ranged from 0.018 to 1.231 mg/L. The CSF:plasma concentration ratio ranged from 0.21 to 2.01. The MIC of dapsone in combination with pyrimethamine against T. gondii is unknown, and further data are required to confirm whether the CSF concentrations of dapsone found in our study are sufficient to inhibit T. gondii growth in patients infected with human immunodeficiency virus (HIV). The high interpatient variability of dapsone CSF concentrations warrants further studies in selected categories of patients with HIV infection.