Rodenticidal Action of 2-Chloro-4-Dimethylamino-6-Methylpyrimidine (Castrix). ∗

Summary and Conclusions

A powerful convulsive agent, Castrix (2-chloro-4-dimethylamino-6-methylpyrimidine) is more toxic to rats than is either alpha-naphthyl-thiourea 1 or sodium fluoroaeetate 2 by oral and parenteral administration. Diets containing 0.25% to 1% of Castrix are readily eaten by rats and are highly toxic. No perceptible sex difference in susceptibility and no noticeable tolerance were observed in rats but some seasonal variation in susceptibility was noted. Sodium pentobarbital is an effective antidote against at least 10 LD₅₀ doses of Castrix in rats and dogs even when administered after convulsions have begun.