An open, randomized, phase III clinical trial of mefloquine and of quinine plus sulfadoxine-pyrimethamine in the treatment of symptomatic falciparum malaria in Brazil.

The clinical and parasitological response of adult male patients to mefloquine and to a combination of quinine and sulfadoxine-pyrimethamine during the treatment of falciparum malaria was compared. These patients were from an area in Brazil where Plasmodium falciparum is showing increasing resistance to quinine and to sulfadoxine-pyrimethamine. The drugs were administered to 100 patients (50 in each group), based on a randomized study design.The rates of clearance of parasitaemia and fever were similar in both groups. However, the parasitological cure rate ("S" response) was 100% for mefloquine but only 92% for quinine plus sulfadoxine-pyrimethamine. Tolerance was good in both groups. The main side-effects (nausea, vomiting, abdominal pain, and dizziness) were mild, transient and required no specific treatment. Nausea and vomiting were more frequent in patients who received quinine plus sulfadoxine-pyrimethamine, while abdominal pain and loose stools or mild diarrhoea were more frequent in the mefloquine group. Tinnitus and hearing difficulty were observed following the administration of quinine plus sulfadoxine-pyrimethamine, but not after mefloquine treatment. Laboratory tests of various haematological and biochemical parameters were not adversely affected in either group after drug administration.It can be concluded that mefloquine, given in a single oral dose of 1000 mg, is highly effective, well tolerated, and safe for the treatment of falciparum malaria in adult males in Brazil.