Effectiveness of combined use of primaquine and clindamycin in the treatment of pneumocystis carinii pneumonia in a rat model

In the present study, the therapeutic effect of primaquine and clindamycin against Pneumocystis carinii pneumonia was evaluated using a rat model. Both primaquine and clindamycin showed no significant effect in reducing the cyst count in the lung when each drug was administered separately at a dose of 1mg/kg/day and 100mg/kg/day, respectively. The combined use of these drugs, however, significantly reduced the cyst count and inflamation in the lung. Furthermore, clindamycin showed a dose-dependent therapeutic effect when used concomitantly with primaquine. It is estimated that the number of patients infected with human immunodeficiency virus will increase in the near future in Japan, necessitating new therapies for P. carinii pneumonia, because of the occasional serious side effects of sulfamethoxazole/trimethoprim and pentamidine, which are commonly used at present. The data in this study indicate the effectiveness of the combined use of primaquine and clindamycin in the treatment of P. carinii pneumonia in an animal model, and indicate the necessity for clinical trials in Japan.