title: [Comparison of sensitivity of artesunate-sensitive and artesunate-resistant Plasmodium falciparum to chloroquine and amodiaquine].
abstract: 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.
authors.affiliation: Yunnan Institute of Malaria Control, Simao 665000.
authors.forename: H
authors.initials: H
authors.lastname: Yang
authors.forename: B
authors.initials: B
authors.lastname: Gao
authors.forename: K
authors.initials: K
authors.lastname: Huang
mesh_terms: 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
chemical_list: D000962:Antimalarials; D037621:Artemisinins; D012717:Sesquiterpenes; D000655:Amodiaquine; D000077332:Artesunate; D002738:Chloroquine