Antifolic combinations in the treatment of malaria.

For the treatment of malaria, combinations of drugs with antifolic action have the great advantage, compared with other drug associations, of synergic action, which increases the effectiveness of the preparation, limits its toxicity, and reduces the risk of resistance. The associations of a sulfonamide (sulfalene, S) with a diaminopyrimidine derivative (pyrimethamine, P, or trimethoprim, T) have given good immediate clinical results. An analysis of the pharmacodynamic and pharmacokinetic characteristics of the three components explains the relative ease with which relapse is encountered with the association ST. The association SP is, from this point of view, more logical and effective and its importance in prophylaxis is surveyed in the light of a critical discussion of the arguments that are at present throwing doubt on the usefulness of its wider employment.