Article date: October 2001
By: Shu‐Qiu Zhang, Trinh Ngoc Hai, Kenneth F. Ilett, Dinh Xuan Huong, Timothy M. E. Davis, Michael Ashton, in Volume 52, Issue 4, pages 377-385
Aims To investigate whether coadministration of the antimalarials artesunate and artemisinin alters the clearance of either drug.
Methods Ten healthy Vietnamese males (Group AS) were randomized to receive a single dose of 100 mg oral artesunate (pro‐drug of dihydroartemisinin) on day −5 and then once daily for 5 consecutive days (days 1–5). Oral artemisinin (500 mg) was coadministered on days 1 and 5. Another 10 subjects (Group AM) were given 500 mg oral artemisinin on day −5 and then further doses on days 1–5. Artesunate 100 mg was given on days 1 and 5. Artemisinin and dihydroartemisinin plasma concentrations on days −5, 1 and 5 were quantified by h.p.l.c. with on‐line postcolumn derivatization and u.v. detection.
Results In Group AS, dihydroartemisinin oral clearance values (mean (95% CI)) were similar on day 1 (32 (22, 47)) l h−1 and day 5 (38 (28, 51)) l h−1 of daily artesunate administration but these mean values were approximately three fold higher compared with day −5 after a single dose (95 (56, 159)). In this group, artemisinin oral clearance increased from 196 (165, 232) l h−1 on day 1–315 (241, 410) l h−1 on day 5. In Group AM, dihydroartemisinin oral clearance on day 1 was 39 (34, 46) l h−1 and increased 1.6 fold to 64 (48, 85) l h−1 on day 5. In this group, artemisinin oral clearance increased sequentially (1.5 and 4.7 fold, respectively) from 207 (151, 285) l h−1 on day −5–308 (257, 368) l h−1 on day 1 and to 981 (678, 1420) l h−1 on day 5. The increase in artemisinin oral clearance between days −5 and 1 (in the absence of artesunate) was similar to that between days 1 and 5 in Group AS subjects who took daily artesunate. Dihydroartemisinin was not a significant metabolite of artemisinin.
Conclusions Artesunate (dihydroartemisinin) did not alter the elimination of artemisinin. However, dihydroartemisinin elimination was inhibited by artemisinin. Artemisinin induced its own elimination even 5 days after a single oral dose. There was no evidence for the formation of dihydroartemisinin from artemisinin.
DOI: 10.1046/j.0306-5251.2001.01461.x
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