Metoprolol is a beta-adrenergic blocking agent. Metoprolol blocks the action of the sympathetic nervous system, a portion of the involuntary nervous system. The sympathetic nervous system stimulates the pace of the heart beat. By blocking the action of these nerves, metoprolol reduces the heart rate and is useful in treating abnormally rapid heart rhythms. Metoprolol also reduces the force of heart muscle contraction and lowers blood pressure. By reducing the heart rate and the force of muscle contraction, metoprolol reduces heart muscle oxygen demand. Since angina occurs when oxygen demand of the heart exceeds supply, metoprolol is helpful in treating angina.
Metoprolol (metoprolol tartrate) is a beta-adrenergic receptor blocking agent. The beta-blocking activity of Metoprolol (metoprolol tartrate) in man including reduction in heart rate and cardiac output at rest and upon exercise, reduction of systolic blood pressure upon exercise, inhibition of isoproterenol-induced tachycardia, and reduction of reflex orthostatic tachycardia. By blocking catecholamine-induced increases in heart rate, in velocity and extent of myocardial contraction, and in blood pressure, Metoprolol (metoprolol tartrate) reduces the oxygen requirements of the heart at any given level of effort, thus making it useful in the long-term management of angina pectoris. However, in patients with heart failure, beta-adrenergic blockade may increase oxygen requirements by increasing left ventricular fiber length and end-diastolic pressure.
Metoprolol belongs to a group of medicines called beta-blockers, which block beta receptors in the heart, lungs and other organs of the body. Blocking these receptors prevents the action of two chemicals called noradrenaline and adrenaline that occur naturally in the body. These are often referred to as the 'fight or flight' chemicals as they are responsible for the body's reaction to stressful situations.
Metoprolol is used to treat high blood pressure. It also is used to prevent angina (chest pain) and heart attacks. It works by relaxing your blood vessels so your heart doesn't have to pump as hard. This medication is sometimes prescribed for other uses; ask your doctor or pharmacist for more information. Metoprolol also is used to treat abnormal heart rhythms.