title: Blood stage antimalarial efficacy of primaquine in Plasmodium vivax malaria.
abstract: The blood stage antimalarial efficacy of primaquine (0.25 mg of base/kg of body weight/day over 14 days) and chloroquine (25 mg of base/kg over 3 days) were compared in 85 adult Thai men with acute Plasmodium vivax malaria. Most (75%) had at least one malaria episode previously. Parasite clearance times after primaquine alone (n = 30) were slower than after chloroquine (n = 30) or combined chloroquine-primaquine (n = 25), but all patients had a satisfactory initial therapeutic response. P. vivax malaria recurred in 10 (17%) of 60 patients followed for > or = 2 months and Plasmodium falciparum malaria developed in another 5 (8%) without reexposure to infection. Recurrences occurred < or = 5 weeks after primaquine treatment (n = 4), suggesting recrudescence, whereas recurrences after chloroquine treatment (n = 6) occurred > or = 5 weeks later, suggesting relapse. Vivax malaria responds well initially to either primaquine or chloroquine. The blood stage antimalarial activity of primaquine may mask chloroquine resistance in combined regimens.
authors.affiliation: Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
authors.forename: S
authors.initials: S
authors.lastname: Pukrittayakamee
authors.forename: S
authors.initials: S
authors.lastname: Vanijanonta
authors.forename: A
authors.initials: A
authors.lastname: Chantra
authors.forename: R
authors.initials: R
authors.lastname: Clemens
authors.forename: N J
authors.initials: NJ
authors.lastname: White
mesh_terms: D000293:Adolescent; D000328:Adult; D000818:Animals; D002738:Chloroquine / Q000627:therapeutic use*; D004351:Drug Resistance; D004359:Drug Therapy, Combination; D005500:Follow-Up Studies; D006801:Humans; D016780:Malaria, Vivax / Q000097:blood / Q000188:drug therapy*; D008297:Male; D008875:Middle Aged; D011319:Primaquine / Q000627:therapeutic use*; D012008:Recurrence; D013785:Thailand; D016896:Treatment Outcome
chemical_list: D002738:Chloroquine; D011319:Primaquine