Background: Azithromycin has demonstrated in vitro and in vivo activity against Plasmodium falciparum, but small treatment studies have given mixed results.
Methods: Participants with fever and with both a blood smear and a rapid diagnostic test positive for falciparum malaria were randomly assigned to groups that were treated with either azithromycin or chloroquine or to matched groups receiving a placebo. After an interim analysis, open-label combination therapy with both drugs was initiated.
Results: At day 28, 5 (33%) of 15 participants in the azithromycin-treated group had remained free of fever, compared with 4 (27%) of 15 in the chloroquine-treated group. All subsequently enrolled participants then received combination therapy with azithromycin and chloroquine. In 61 (97%) of 67 participants, resolution of fever and parasitemia had occurred by day 7, and, through day 28, no clinical or parasitologic relapse had occurred in them.
Conclusions: Resolution of parasitemia was inadequate with monotherapy with either azithromycin or chloroquine, but combination therapy provided substantially improved clinical and parasitologic outcomes. The combination of azithromycin and chloroquine may be an effective alternative treatment for falciparum malaria and deserves further study.