Pyrantel is a carboxamidine and 1,4,5,6-tetrahydropyrimidine substituted at position 1 with a methyl group and at position 2 with an (E)-2-(2-thienyl)vinyl group. It is used as the embonate salt [4,4'-methylenebis(3-hydroxy-2-naphthoate)] as an anthelmintic effective against intestinal nematodes, including threadworms, roundworms, and hookworms. It is listed in the WHO Model List of Essential Medicines and functions as an antinematodal drug. It belongs to thiophenes, carboxamidines, and 1,4,5,6-tetrahydropyrimidines.
