Chloroquine and quinine: a randomized, double-blind comparison of efficacy and side effects in the treatment of Plasmodium falciparum malaria in the Philippines.

Chloroquine (25 mg/kg over 3 d) was compared to quinine (10 mg/kg 3 times daily for 5 d) in 20 adult Filipino males with uncomplicated Plasmodium falciparum malaria in a double-blind, randomized trial. Asexual parasitaemia was cleared in all patients, with no statistically significant difference (P = 0.13) in the rate of clearance between the chloroquine-treated patients (76.1 +/- 29.3 h) and those receiving quinine (60.3 +/- 12.5 h). The duration of fever was also comparable (chloroquine 46.3 +/- 24.7 h; quinine 43.2 +/- 20.0 h; P = 0.76) and 40% of patients in each treatment group experienced mild side effects. Chloroquine, however, is cheaper and easier to administer. In vitro results were strikingly different. P. falciparum parasites from 4 quinine-treated patients were all sensitive to this compound in vitro, whereas 4 of the 5 isolates from the chloroquine group were resistant. Further comparisons of these two antimalarials are indicated, especially in cerebral malaria, and drug use policies should be based on clinical and parasitological response to treatment.