ACTIVITY OF AZITHROMYCIN AS A BLOOD SCHIZONTICIDE AGAINST RODENT AND HUMAN PLASMODIA IN-VIVO

We compared the efficacy of azithromycin to the clinical antimalarial doxycycline in Plasmodium berghei-infected mice and in P. falciparum-i nfected Aotus monkeys. When mice were administered drug orally twice a day for three days, the minimum total dose of azithromycin that cured all mice was 768 mg/kg. Doxycycline at a dose of 1,536 mg/kg cured no mice. The efficacy of fast-acting blood schizonticides (quinine, halo fantrine, artemisinin) against P, berghei was augmented by azithromyci n. In monkey experiments in which there were two animals per experimen tal group, azithromycin (100 mg/kg/day for seven days) eliminated para sitemia; azithromycin (30 mg/ kg/day) initially cleared 99.8-100% of t he parasites with recrudescence in the one completely cleared case. Do xycycline (30 mg/kg/day) cleared 100% of the parasites with recrudesce nce in both cleared cases. Since azithromycin can be clinically admini stered at a somewhat higher daily dosage than doxycycline, the data su ggest that it may be possible to replace drugs of the tetracycline cla ss with azithromycin in combination with fast-acting blood schizontici des for the treatment of P. falciparum infection.