A single dose of intramuscular sulfadoxine-pyrimethamine as an adjunct to quinine in the treatment of severe malaria: pharmacokinetics and efficacy.

It has been suggested that sulfadoxine-pyrimethamine (SD/PM) may be useful in the treatment of severe malaria since it could enhance the killing of parasites by quinine (QN) and it can be given as a single intramuscular injection. Eighty Kenyan children with severe malaria were allocated at random to receive either intramuscular QN alone (quinine dihydrochloride 20 mg salt/kg as a loading dose, followed by 10 mg salt/kg 12 hourly for a total of 6 doses) or the same QN regimen plus one intramuscular injection of SD/PM (sulfadoxine 25 mg/kg, pyrimethamine 1.25 mg/kg). There was no difference in time to defervescence, aparasitaemia, or 50% reduction in parasitaemia, parasite elimination half-life, or mortality between the 2 groups. In addition, the concentrations of SD and PM were measured in 14 children and of QN in 8 of these children. Concentrations needed to achieve synergy against PM-resistant strains of Plasmodium falciparum were achieved in all of the children with severe malaria within the first hour and maintained for more than 72 h. SD/PM did not perturb the pharmacokinetics of QN.