The long-acting 8-aminoquinoline tafenoquine (TQ) coadministered with chloroquine (CQ) may radically cure Plasmodium vivax malaria. Coadministration therapy was evaluated for a pharmacokinetic interaction, and pharmacodynamic, safety and tolerability characteristics.
Healthy subjects, 18-55 years old, without documented glucose-6-phosphate dehydrogenase deficiency received CQ alone (Days 1-2: 600 mg, Day 3: 300 mg), TQ alone (Days 2-3: 450 mg), or coadministration therapy (Day 1: CQ 600 mg; Day 2: CQ 600 mg+TQ 450 mg; Day 3: CQ 300 mg+TQ 450 mg) in a randomized, double-blind, parallel-group study. Blood samples for pharmacokinetic and pharmacodynamic analyses and safety data, including electrocardiograms, were collected for 56 days.
CQ+TQ had no effect on TQ AUC0-t , AUC0-∞ , Tmax , or t1/2 . The 90% confidence intervals of CQ+TQ:TQ for AUC0-t , AUC0-∞ , and t1/2 indicated no drug interaction. On Day 2 of CQ+TQ coadministration, TQ Cmax and AUC0-24 increased 38% (90% CI 1.27,1.64) and 24% (90% CI 1.04,1.46), respectively. The pharmacokinetics of CQ and its primary metabolite desethylchloroquine were not affected by TQ. Coadministration had no clinically significant effect on QT intervals, and was well tolerated.
No clinically significant safety or pharmacokinetic / pharmacodynamic interactions were observed with coadministered CQ and TQ in healthy subjects.
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