• 1.

    Pinichpongse S., Doberstyn E. B., Cullen J. R., Yisunsri Laksami, Thongsombun Y., Thimasam K., 1982. An evaluation of five regimens for the outpatient therapy of falciparum malaria in Thailand 1980–1981. Bull. W.H.O. 60: 907912.

    • Search Google Scholar
    • Export Citation
  • 2.

    Marchiafava E., 1931. Pernicious malaria. Am. J. Hyg., 13: 156.

  • 3.

    Gutteridge W. E., Trigg P. I., 1968. Action of pyrimethamine on P. knowlesi. Parasitology, 62: 431444.

  • 4.

    Aikawa M., Beaudoin R. L., 1968. Studies on nuclear division of a malarial parasite under pyrimethamine treatment. J. Cell. Biol., 39: 749754.

    • Search Google Scholar
    • Export Citation
  • 5.

    Weidekamm E., Plozza-Nottebrock H., Forgo I., Dubach V. C., 1982. Plasma concentrations of pyrimethamine and sulfadoxine and evaluation of pharmacokinetic data by computerized curve fitting. Bull. W.H.O., 60: 115122.

    • Search Google Scholar
    • Export Citation
  • 6.

    Edstein M., 1984. Pharmacokinetic studies of Maloprim and Fansidar in man. M.Sc. thesis, University of Sydney.

  • 7.

    Thaithong S., Beale G. H., 1981. Resistance of ten Thai isolates of Plasmodium falciparum to chloroquine and pyrimethamine by in vitro tests. Trans. R. Soc. Trop. Med. Hyg., 75: 271273.

    • Search Google Scholar
    • Export Citation
  • 8.

    World Health Organization, 1973. Chemotherapy of malaria and resistance to antimalarials. WHO Tech. Rep. Ser. No. 529: 1921.

 

 

 

 

Response of Plasmodium Falciparum Infections to Pyrimethamine-Sulfadoxine In Thailand

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  • Army Malaria Research Unit, Milpo, Ingleburn 2174, Australia, Malaria Division, Ministry of Health, Bangkok 10200, Thailand, and World Health Organization, Bangkok 10200, Thailand

The results of this study in Thailand indicate that the early response of falciparum infections to a single dose of pyrimethamine-sulfadoxine is influenced by the developmental stages of the parasite present at the time of treatment. Parasite clearance is slower when young rings predominate at the time of treatment. This should be taken into account when considering the clinical management of patients and the comparative efficacy of antimalarials in clearing parasites from the peripheral blood. The 36–48 hr delay in schizonticidal action observed after treatment of febrile infections and the associated decline in blood concentrations of pyrimethamine suggest that a single dose may not be the ideal way of administering this drug combination and may encourage the emergence of drug-resistant parasites.

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