PLENDIL (felodipine) is a calcium antagonist (calcium channel blocker). Felodipine is a dihydropyridine derivative that is chemically described as ethyl methyl 4-(2,3-dichlorophenyl)-1,4- dihydro-2,6-dimethyl-3,5-pyridinedicarboxylate. Its empirical formula is C18H19Cl2NO4 and its structural formula is: