<p>Diltiazem hydrochloride is a calcium channel antagonist. It is a peripheral and coronary vasodilator with some negative inotropic activity. Diltiazem inhibits cardiac conduction particularly at the sino-atrial and atrioventricular nodes. Diltiazem has the following actions:<br />
<br />
<strong>Antianginal</strong>: A direct dilatation of coronary arteries and arterioles proved oxygen supply to myocardial tissues. In addition dilatation of the peripheral vasculature reduces systemic pressure of cardiac &quot;after load&quot; which results in lessened stress and reduced oxygen requirements of the myocardial tissues.<br />
<br />
<strong>Antiarrhythmic</strong>: The inhibited influx of calcium ions in cardiac tissues result in slowed electrophysiological activity through the S-A and A-V nodes without affecting accessory bypass conduction or altering normal atrial action potential or intraventricular conduction.<br />
<br />
<strong>Antihypertensive</strong>: Reduces peripheral vascular resistance as a result of vasodilatation. More than 90% of an oral dose is rapidly absorbed. Protein binding is very high. Peak plasma concentration reaches within 30-60 minutes. It is metabolised in the liver and excreted (60%) through bile.</p>