DHFR and malaria: Pyrimethamine selectively inhibits dihydrofolate reductase (dhfr), a part of the folate pathway in the malaria parasites, and Plasmodium falciparum resistance, both in vivo and in vitro, has been associated with specific point mutations (A16V, N51I, C59R, S108N/T and I164L) in the dhfr gene [9, 10].