nifedipine, and diltiazem hydrochloride are all slow calcium-channel
antagonists that reduce influx of calcium to the cell, resulting in
vasodilation of vascular smooth muscle and increased coronary blood flow,
especially to the epicardial region. These drugs have complex mechanisms
of action. Slow calcium-channel blockers have a rather selective effect
on cardiovascular functions, with a direct action on the smooth muscle
of the arteries.