Beta-adrenergic blocking agents
Beta adrenergic blocking agents prevent stimulation of the beta adrenergic receptors at the nerve endings of the sympathetic nervous system and therefore decrease the activity of the heart. They block sympathetic stimulation of the heart and reduce systolic pressure, heart rate, cardiac contractility and output, so decrease myocardial oxygen demand and increase exercise tolerance.
Beta adrenergic blocking agents are used to treat angina, control abnormal heart rhythms and to reduce high blood pressure. However, blocking of the beta receptors may cause bronchial constriction therefore care has to be taken with the use of beta blockers in patients with respiratory conditions.