New prophylactic treatments against malaria: doxycycline and atovaquone-proguanil.

Doxycycline - The efficacy and tolerance of doxycycline for chemoprophylaxis against malaria have been the subject of numerous studies. The main findings can be summarized as follows: - Efficacy: Doxycycline has proven effective against Plasmodium falciparum malaria (100 mg per day). Reported efficacy rates range between 84 and 98% for all but one study, with a rate of 64%. - Adverse effects: Tolerance at the dose of 100 mg per day was good in most studies. Discontinuation due to poor tolerance was necessary for 0.6 to 12% of the cases. The most common adverse effect (diarrhea, nausea) affected between 18 and 49% of the subjects. Minor phototosensitivity was observed in 0 to 21% of the cases. Randomized placebo-controlled studies demonstrated excellent tolerance with a similar incidence of digestive disorders in the placebo groups. - Official recommendations: The "Conseil superieur d'hygiene publique de France", the World Health Organization, and the Center for Disease Control and Prevention in Atlanta have all recommended the prescription of doxycycline as chemoprophylaxis for persons traveling to areas with mefloquine-resistant plasmodium strains (some regions in Thailand, Cambodia, and Vietnam) and for patients with intolerance or contraindications to mefloquine. Atovaquone-proguanil - Only two studies, involving 247 patients, have been published concerning the efficacy and tolerance of atovaquone-proguanil for the chemoprophylaxis of P. falciparum malaria. Both authors conclude that the combination was highly effective and well tolerated. further studies will be necessary and it is too early to recommend prophylactic use of this combination for Plasmodium falciparum malaria. (C) 1999 Editions scientifiques et medicales Elsevier SAS.