<p><strong>Atenolol</strong>&nbsp;belongs to a group of medicines called beta-blockers. It has an effect on the heart by blocking the action of chemicals called noradrenaline and adrenaline on beta receptor and control its rate and rhythm of beating. By reducing the heart rate and the force of muscle contraction, atenolol reduces the need of heart muscle for oxygen (demand). Because angina occurs when oxygen demand of the heart exceeds supply, atenolol is helpful in treating angina.<br />
<br />
<strong>Nifedipine</strong>&nbsp;belongs to a group of medicines called calcium-channel blockers. These medicines block the transport of calcium, via holes called channels, into the smooth muscle cells lining the heart blood vessels and other blood vessels of the body. Blocking calcium transport relaxes the muscles of the blood vessels and makes them wider.</p>