Therapeutic efficacy of chloroquine against uncomplicated, Plasmodium falciparum malaria in south-western Saudi Arabia

Ann Trop Med Parasitol. 2001 Dec;95(8):773-9. doi: 10.1080/0003498012011127.


The results of annual random screening indicated that Plasmodium falciparum strains showing chloroquine (CQ) resistance in vitro became increasingly common in the Jazan region of south-western Saudi Arabia between 1986 and 1998 (chi(2) for trend = 50.027; P < 0.001). This worrying trend and the emergence of a micro-epidemic in 1997-1998 prompted an assessment of the therapeutic efficacy of CQ against uncomplicated, P. falciparum malaria in the area. The in-vivo testing of sensitivity to CQ was carried out in 291 clinically manifest, microscopically positive cases of P. falciparum malaria. Most of these patients (88%) were successfully treated with a single standard regimen of CQ therapy. The other 36 patients (12%) showed early treatment failure or a poor response to the CQ, although all of these were then successfully treated with a single standard dose of sulfadoxine-pyrimethamine (Fansidar), as a replacement therapy. Those unsuccessfully treated with CQ were generally younger (t = 2.625; P = 0.01) and tended to have higher body temperatures (t = -2.62; P = 0.012) and higher levels of parasitaemia at initial presentation (P > 0.000) than those who responded well to the drug. Although CQ remains a reasonably effective drug for the treatment of malaria in the Jazan region, and therefore will be kept as the first-line drug for the foreseeable future, failure of CQ efficacy must be carefully monitored in the area.

Publication types

  • Clinical Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acute Disease
  • Adolescent
  • Adult
  • Aged
  • Animals
  • Antimalarials / therapeutic use*
  • Child
  • Child, Preschool
  • Chloroquine / therapeutic use*
  • Drug Resistance
  • Humans
  • Incidence
  • Infant
  • Malaria, Falciparum / drug therapy*
  • Malaria, Falciparum / epidemiology
  • Middle Aged
  • Parasitemia / drug therapy
  • Parasitic Sensitivity Tests / methods
  • Plasmodium falciparum / drug effects
  • Saudi Arabia / epidemiology
  • Treatment Failure


  • Antimalarials
  • Chloroquine