RANDOMIZED PLACEBO-CONTROLLED TRIAL OF PRIMAQUINE FOR PROPHYLAXIS OF FALCIPARUM AND VIVAX MALARIA

Drug resistance has made malaria prevention difficult and the new agen ts are too expensive for widespread use, Primaquine, an established dr ug for treatment, is potentially useful for prevention, Malaria prophy laxis with primaquine was evaluated in Irian Jaya during one year in J avanese men who were not deficient in glucose-6-phosphate dehydrogenas e (G-6-PD). 126 volunteers were randomised to receive 0 . 5 mg/hg prim aquine base or placebo daily (double-blinded), or 300 mg chloroquine b ase weekly (open). The protective efficacy of primaquine relative to p lacebo was 94 . 5% (95% confidence interval 57-99) for Plasmodium falc iparum and 90 . 4% (95% CI 58-98) for P vivax, Attack rates for either parasite did not differ significantly between the chloroquine and pla cebo groups. Incidence density of physical complaints not associated w ith parasitaemia was low (17-18 complaints/person-year) and was about the same in all groups except for cough, which was increased in the pr imaquine group. Complete blood counts were normal and no evidence of h epatic or renal dysfunction was found with primaquine. However, at 50 weeks the primaquine group had a mean methaemoglobin of 5 . 8% (range 1 . 4-13%), which declined by half within 7 days of ending prophylaxis . When used daily for one year by men with normal G-6-PD activity, pri maquine was well tolerated and effective for prevention of malaria.