The pharmacokinetics of chloroquine in healthy Thai subjects and patients with Plasmodium vivax malaria.

The pharmacokinetics of chloroquine (CQ) and desethylchloroquine (DECQ) were studied in seven male Thai patients with P. vivax malaria and seven healthy male Thais, after the standard oral dosage regimen of CQ (a total dose of 1500 mg given over 3 days). All patients showed a rapid initial response to the treatment with median (range) values of fever and parasite clearance times of 13.7 (2-47) and 58 (33-38) h, respectively. In the patients, the median range Cmax value was significantly higher (1547 (996-2446) vs 838 (656-1587) ng ml-1), and AUC(0,28d) was greater (281 (250-515) vs 122 (103-182) micrograms ml-1 h). In addition, the median (AUC(0,28d) of DECQ was significantly greater (170 (72-265) vs 77 (49-140) micrograms ml-1 h). The AUC(0,28d) ratio of DECQ to CQ in patients was significantly higher than that in healthy subjects (0.67 (0.43-0.90) vs 0.51 (0.29-0.61)).