Artemether or artesunate followed by mefloquine as a possible treatment for multidrug resistant falciparum malaria

Plasmodium falciparum in south-east Asia is highly resistant to chloroquine and sulfadoxine-pyrimethamine. Mefloquine used to be the chemosuppressant drug of choice in areas with chloroquine resistance. However, sensitivity to this drug has recently decreased in Thailand, Cambodia and Myanmar, and there is no suitable single alternative drug. We therefore investigated possible alternative combination therapies for multidrug resistant falciparum malaria. 120 male Thai patients at Makarm Malaria Clinic, Chantaburi, in eastern Thailand were allocated at random to receive either oral artemether (group A) or artesunate (group B) at a single dose of 300 mg on day 1, both followed by mefloquine, 750 and 500 mg at 24 and 30 h, respectively. Follow-up was on days 1, 2, 7, 14, 21, 28, 35 and 42. Patients in both groups had a rapid initial response to treatment; in most cases parasitaemia was cleared within 24 h, and fever was cleared within 24 h in 62% and 76.7% of the patients in groups A and B, respectively. 58 patients in group A and 57 in group B completed follow-up and cure rates were 98% and 97%, respectively. Reinfection could not be excluded for the 3 patients with recrudescences; all were cured with a repeated course of treatment. No serious adverse effect was observed in either group, only mild and transient nausea, vomiting and loss of appetite, with no significant difference between the 2 groups. These results suggest that a single oral dose of 300 mg of either artemether or artesunate followed by 1250 mg of mefloquine in 2 divided doses is effective against multiple drug resistant falciparum malaria. Either regimen can be considered as a suitable 'stand-by' in endemic areas of multiple drug resistant falciparum malaria.