Can the course of high dose cotrimoxazole for Pneumocystis carinii pneumonia in AIDS be shorter? A possible solution to the problem of cotrimoxazole toxicity.

Fifty consecutive patients with confirmed PCP received a high dose of cotrimoxazole for 14 d, or until development of intolerance, directly followed by reduced dose maintenance therapy. Seven individuals died during the high dose course. Twenty (47%) of the 43 survivors showed toxicity reactions that necessitated dose reduction to maintenance level on average after 9.6 d. Thirteen of these 20 individuals tolerated the reduced dose, and seven did not. No further cases of toxicity were observed. In 43 survivors only one early relapse (day 17) was observed in a patient who had received full dose treatment for 14 d. We conclude (1) that extending high dose cotrimoxazole therapy beyond 2 weeks is usually unnecessary, provided that reduced dose maintenance therapy is given directly, and (2) that dose reduction on appearance of toxicity signs during the second week of treatment is safe and allows two-thirds of patients to be maintained on cotrimoxazole with satisfactory results.