Effects of Folic Acid and Folinic Acid on Pyrimethamine Teratogenesis in Rats

ABSTRACT  The effects of folic acid (FA) and folinic acid (FNA) on the tera-togenicity of the antifolate drug pyrimethamine (PYR) were examined in rats. PYR and FA were orally administered with mashed feed. FNA was intraperitoneal-ly injected. The drugs were administered for 5 days of day 11–15 of gestation. Six groups were made; G-I PYR 1.6 (mg/kg/day), G-II PYR 3.6, G-HI PYR 1.6 + FA 50, G-IV PYR 3.6 + FNA 12, G-V FA 50, G-VI control. No malformations were found in G-I, IV, V and VI. All fetuses in G-II and HI had malformations. Main malformations in G-II and III were cleft palate and brachygnathia. Accordingly it might be demonstrated that the teratogenicity of PYR was potentiated by concurrent FA in rats.