A comparison of the pharmacokinetics of mefloquine in healthy Thai volunteers and in Thai patients with falciparum malaria.

We have studied the kinetics of a single oral dose of mefloquine (750 mg) in 12 Thai patients with falciparum malaria and have compared the results with those of a previous study in 12 healthy Thai volunteers. All the patients responded to treatment with a mean parasite clearance time of 66.6 h and a mean fever clearance time of 54.1 h. There was no significant difference in peak plasma concentration, time to peak, area under the curve or apparent volume of distribution between patients and controls. However, the terminal half-life (t1/2) and mean residence time (MRT) were shorter in the patients (12.2 vs 16.7 days for t1/2 and 15.5 vs 21.4 days for MRT). We conclude that there are changes in the disposition of mefloquine related to malaria, although the exact basis of the changes is not clear.