Field trials with chlorproguanil in the prophylaxis of malaria in Ghana.

Chlorproguanil is one of the antimalarial drugs developed in recent years which have shown promise for field use in malaria eradication campaigns. It has been demonstrated to possess properties similar to those of proguanil but with a more persistent action. The author reports the results obtained in four field trials with this drug in Ghana.Chlorproguanil was shown to have a rapid action on asymptomatic parasitaemias of P. falciparum and P. malariae (exclusive of crescents) in Ghanaian schoolchildren. In weekly doses of 20 mg it protected a group of children from reinfection for four weeks, but thereafter irregular dosage was associated with a small number of break-throughs by P. falciparum. By the end of six months there was strong evidence of P. falciparum resistance to the drug. Evidence was also found in P. falciparum infections of cross-resistance between chlorproguanil and pyrimethamine.Unlike pyrimethamine, chlorproguanil was not secreted in the maternal milk in sufficient quantity to be of therapeutic value to young, wholly breast-fed infants.The author considers that, while this drug might serve as an effective weekly prophylactic in households where the regimen would be strictly followed, it would not be suitable for long-term community use in rural tropical Africa.