Barnidipine hydrochloride, chemically known as (3S)-1-benzyl-3-pyrrolidinylmethyl-(4S)-2,6-dimethyl-4-(m-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate hydrochloride, is a new long-acting dihydropyridine calcium antagonist developed and marketed by Yamanouchi Pharmaceutical (now Astellas Pharma). This medication effectively lowers blood pressure without impacting heart rate by specifically targeting calcium channels responsible for transmembrane potential. By inhibiting calcium influx into cells, it selectively relaxes smooth muscle in peripheral and coronary blood vessels.