Treatment of Pneumocystis carinii pneumonitis with trimethoprim-sulfamethoxazole.

Pneumocystis carinii pneumonitis (PCP) is fatal in 90 to 100% of the cases if no treatment is given. Trimethoprim-sulfamethoxazole (TMP-SMX) was used at one of two dosage levels in the treatment of 20 children with PCP and cancer. Of 14 patients treated with 20 mg TMP--100 mg SMX/kgd, 12 recovered and 2 died. Treatment of the fatal cases and one of the patients who recovered was supplemented with pentamidine. When six patients were treated with 4 to 7 mg TMP--20 to 35 mg SMX/kgd, four recovered and two died. Both fatal cases and one of the patients who recovered were also treated with pentamidine. There was no significant adverse effects from TMP-SMX.