Malaria suppression with fortnightly doses of pyrimethamine with sulfadoxine in the Gambia.

As it had been shown in previous trials that very small doses of pyrimethamine and sulfadoxine or dapsone were effective in eliminating Plasmodium falciparum in 2 or 3 days, small-scale field trials were carried out on children to investigate the efficacy of this combination of drugs in suppressing malaria.Doses of pyrimethamine 2 mg with sulfadoxine 40 mg, fortnightly, appeared to be completely successful in suppressing seasonal hyperendemic malaria in a group of 38 Gambian children over a 6-month period. On the other hand, pyrimethamine alone at the recommended dose failed to suppress falciparum malaria in some children of another group. Parasite resistance to the sulfonamide-pyrimethamine combination was not encountered nor was there any suggestion of toxicity. It is concluded that these drugs in combination could have a place in malaria chemoprophylaxis.