A pharmacokinetic and pharmacodynamic study of intravenous vs oral artesunate in uncomplicated falciparum malaria

Aims To obtain comprehensive pharmacokinetic and pharmacodynamic data for artesunate (ARTS) and its active metabolite dihydroartemisinin (DHA) following i.v. and oral administration of ARTS to patients with acute, uncomplicated falciparum malaria. Methods Twenty-six Vietnamese patients with falciparum malaria were randomized to receive either i.v. ARTS (120 mg; group 1) or oral ARTS (100 mg; group 2), with the alternative preparation given 8 h later in an open crossover design. Mefloquine (750 mg) was administered at 24 h. Plasma concentrations of ARTS and DHA were determined by h.p.l.c. assay. Pharmacokinetic parameters were calculated by non-compartmental methods. The time to 50% parasite clearance (PCT50) was calculated by linear interpolation of parasite density determinations. Linear least squares and multiple linear regression analyses were used to evaluate pharmacokinetic-pharmacodynamic relationships. Results Following i.v. bolus, ARTS had a peak concentration of 29.5 mu M (11 mg l(-1)), elimination t(1/2)=2.7 min, CL=2.33 l h(-1) kg(-1) and V=0.14 l kg(-1). The C-max for DHA was 9.3 mu M (2.64 mg l(-1)), t(1/2)=40 min, CL=0.75 l h(-1) kg(-1) and V=0.76 l kg(-1). Following oral ARTS, relative bioavailability of DHA was 82%, C-max was 2.6 mu M (0.74 mg l(-1)), t(1/2)=39 min, and MAT=67 min. Overall, the PCT50 and fever clearance time (FCT) were 6.5 h and 24 h, respectively. There was no correlation between PCT50 or FCT and AUC, C-max or MRT for DHA. Conclusions Despite rapid clearance of ARTS and DHA in patients with uncomplicated falciparum malaria, prompt parasite and fever clearance were achieved. High relative bioavailability of DHA following oral ARTS administration, and clinical outcomes comparable with those after i.v. ARTS, support the use of the oral formulation in the primary care setting.