[Comparison of sensitivity of artesunate-sensitive and artesunate-resistant Plasmodium falciparum to chloroquine and amodiaquine].
OBJECTIVE
To explore the in vitro sensitivity of artesunate-sensitive and -resistant Plasmodium falciparum to chloroquine and amodiaquine and to observe the effect of artesunate combined with chloroquine and artesunate combined with amodiaquine on artesunate-resistant P. falciparum.


METHODS
The sensitivity of the artesunate-sensitive and -resistant P. falciparum to chloroquine and amodiaquine and their combination with artesunate was compared by using Rieckmann's in vitro micro-technique.


RESULTS
The ID50 and ID95 values of chloroquine, amodiaquine and artesunete were 90.9, 50.9, 9.6 nmol/L and 320.0, 320.0, 40.0 nmol/L to the artesunate-sensitive P. falciparum respectively and were 112.0, 133.5, 85.1 nmol/L and 320.0, 320.0, 400.0 nmol/L to artesunate-resistant P. falciparum, respectively. When artesunate was combined with chloroquine, the ID50 values of the 2 drugs were 3.2 and 20.0 nmol/L to the artesunate-resistant P. falciparum. When artesunate was combined with amodiaquine, the ID95 values of the 2 drugs were 3.2 and 5.0 nmol/L to the artesunate-resistant P. falciparum, respectively.


CONCLUSIONS
The artesunate-resistant P. falciparum has no cross resistance to chloroquine and amodiaquine, however, artesunate combined with chloroquine or amodiaquine exhibit an apparent synergistic effect in vitro.
Yang
H
H
Yunnan Institute of Malaria Control, Simao 665000.
Gao
B
B
Huang
K
K
D000655:Amodiaquine / Q000494:pharmacology*; D000818:Animals; D000962:Antimalarials / Q000494:pharmacology*; D037621:Artemisinins / Q000494:pharmacology; D000077332:Artesunate; D002738:Chloroquine / Q000494:pharmacology*; D004351:Drug Resistance; D004357:Drug Synergism; D010963:Plasmodium falciparum / Q000187:drug effects*; D012717:Sesquiterpenes / Q000494:pharmacology
D000962:Antimalarials; D037621:Artemisinins; D012717:Sesquiterpenes; D000655:Amodiaquine; D000077332:Artesunate; D002738:Chloroquine