Randomized, controlled, double-blind trial of daily oral azithromycin in adults for the prophylaxis of Plasmodium vivax malaria in Western Thailand.

Author(s): Heppner DG Jr, Walsh DS, Uthaimongkol N, Tang DB, Tulyayon S, Permpanich B, Wimonwattrawatee T, Chuanak N, Laoboonchai A, Sookto P, Brewer TG, McDaniel P, Eamsila C, Yongvanitchit K, Uhl K, Kyle DE, Keep LW, Miller RE, Wongsrichanalai C

Affiliation(s): Department of Immunology and Medicine, United States Army Medical Component, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand. donald.heppner@na.amedd.army.mil

Publication date & source: 2005-11, Am J Trop Med Hyg., 73(5):842-9.

Publication type: Randomized Controlled Trial

We assessed the prophylactic efficacy of azithromycin (250 mg/day) against malaria in 276 adults in western Thailand in a randomized, double-blind, placebo-controlled trial. After antimalarial suppressive treatment, volunteers were randomized in a 2:1 ratio to either the azithromycin or placebo, respectively. Study medication was given for an average of 74 days. The azithromycin group (n = 179) had five endpoint parasitemias (1 Plasmodium vivax and 4 P. falciparum), and the placebo group (n = 97) had 28 endpoint parasitemias (21 P. vivax, 5 P. falciparum, and 2 mixed infections). Adverse events and compliance and withdrawal rates were similar in both groups. The protective efficacy (PE) of azithromycin was 98% for P. vivax (95% confidence interval [CI] = 88-100%). There were too few cases to reliably estimate the efficacy of azithromycin for P. falciparum (PE =71%, 95% C =-14-94%). We conclude that daily azithromycin was safe, well-tolerated, and had a high efficacy for the prevention of P. vivax malaria.