Prophylactic drugs for malaria: why do we need another one?

There are currently a limited number of drugs available to prevent malaria in travelers, and new, more efficacious, and better tolerated regimens are urgently needed. Clearly, none of the available regimens are ideal for all travelers, and the travel medicine practitioner should attempt to match the individual's risk of exposure to malaria with the appropriate regimen based on drug efficacy, tolerance, and safety. To facilitate decision making, we have generated a Clinical Utility Score, in which different attributes of each drug regimen, such as efficacy, tolerance, convenience, cost, etc., are estimated based on our experience with these drugs (see Table 1). Other groups and users may weight each variable somewhat differently depending on the specific needs and risk of drug-resistant malaria. For example, a traveler to rural Irian Jaya may weight efficacy more heavily than cost or convenience. Using this scoring strategy, new agents like atovaquone/proguanil and WR 238605 compare favorably to our current options, indicating their potential to fill important holes in our chemoprophylactic arsenal.