Prevention of drug resistance in rodent malaria by the use of drug mixtures.

Development of resistance to chloroquine in rodent malaria is inhibited by giving this compound together with a potentiating mixture of pyrimethamine and sulfadoxine but this does not prevent the development of resistance to the last two compounds. The use of drug mixtures should be explored as a means of "protecting" chloroquine or new blood schizontocides intended for mass chemotherapy against human malaria. However, no general rule can be laid down without testing specific drug mixtures in long-term experiments in a suitable model such as rodent malaria.