NEW ANTIMALARIALS - A RISK-BENEFIT ANALYSIS

Although more than 40% of the world's population live in malaria endem ic areas, there are only 6 available antimalarial drugs for the treatm ent of Plasmodium falciparum infections. Three of these have been deve loped in the last 20 years and are discussed in this review. Mefloquin e is relatively well tolerated and has the advantage of a. single day regimen. It has ideal properties for prophylactic use. However, althou gh rare, serious adverse reactions do occur and the drug cannot be use d in severe malaria. Resistance has already emerged in some parts of t he world, Halofantrine is also well tolerated and has a rapid antimala rial activity. It is more expensive than other antimalarials and the e xistence of cross-resistance links its usefulness to the demise of mef loquine, The discovery of a potentially lethal cardiotoxicity associat ed with halofantrine casts a further shadow over its use. The artemisi nin derivatives represent an exciting breakthrough in the treatment of malaria. They are cheap and have a very rapid action. They seem remar kably free from toxic adverse effects, although the neurotoxicity seen in animal studies with the liposoluble derivatives gives rise for con cern. However, the lack of pharmacokinetic and toxicity data as yet pr eclude their approval by Western drug regulation authorities. All anti malarials are threatened by the emergence of parasite resistance. Comb ination therapy using mefloquine and an artemisinin derivative may pro vide a way in which resistance can be combated.