Efficacy of sulfadoxine/pyrimethamine in the treatment of uncomplicated Plasmodium falciparum malaria in Republic of Congo

Congo is facing frequent failures of treatment of Plasmodium falciparum malaria with chloroquine (CQ), which is still recommended and used as a first-line drug. In Pointe-Noire and Brazzaville, the two largest cities that contain approximately 60% of the population of Congo, we compared the efficacy of CQ versus sulfadoxine/pyrimethamine (SP) for treatment of uncomplicated malaria in children 6-59 months old (mean = 33 months) using the standard World Health Organization (WHO) 14-day in vivo test in two phases between 1999 and 2002. Patients enrolled were randomly assigned to receive SP (25 mg/kg of sulfadoxine and 1.25 mg/kg of pyrimethamine) or CO (25 mg/kg). In the first phase of the study, 46 patients were assigned to the CQ (n = 23) or SP (n = 23) groups in Pointe-Noire and 52 children were assigned to the CQ (n = 26) or to SP (n = 26) groups in Brazzaville. Results were interpreted according to the WHO lot quality assurance sampling method, and treatment failure rates for SP versus CQ were < 25% versus > 25% in both cities. In the second phase of the study, we accurately determined the actual proportion of treatment failures for SP in Brazzaville. Thus, in 75 of the 80 children enrolled and followed-up until day 14, no clinical or parasitologic failure was recorded and no serious adverse reaction was observed. Since the CQ treatment failure rate exceeds the unacceptable upper limit, SP seems well to be an appropriate alternative for the first-line treatment of uncomplicated P. falciparum malaria, at least in the settings of the present study.