Double-blind trial to find dose range using a fixed combination of mefloquine, sulfadoxine and pyrimethamine in falciparum malaria: a field study on adults in Burma

Abstract

In a field study conducted in Burma, 60 semi-immune adults were randomly assigned to 2 treatment groups. The first (mean parasite count, 12717/mm 3) received a single dose of a fixed combination of 500 mg mefloquine base, 1000 mg sulfadoxine and 50 mg pyrimethamine (2 tablets of ‘Fansimef’) plus 1 tablet placebo. The second group (mean parasite count, 11 863/mm 3) were given 3 tablets of the same medication. The study was double-blind. Parasite count was checked daily for the first week and weekly for a further 3 weeks. Average times for parasite clearance were 1·47 d in patients receiving 2 tablets, and 1·87 d in those given 3 tablets. Asexual parasites reappeared on day 28 in one patient in each group, although they had been free of parasites during the previous 4 weeks; this could be due to reinfection. The drugs were generally well tolerated, though mild and transient giddiness was seen in 80% of patients in the first group and 96% in the second. Nausea was reported by 33% and 43% of patients respectively. No vomiting occurred in the first group but 8 patients vomited in the second ( P < 0·01). In conclusion it seems possible to treat falciparum malaria in semi-immune adults, weighing less than 60 kg, with a single dose of 500 mg mefloquine base, 1000 mg sulfadoxine and 50 mg pyrimethamine (2 tablets), instead of the higher dose (3 tablets) currently recommended. This reduces treatment cost and improves tolerance of the drugs.