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Revision as of 02:15, 7 February 2003 by AxelBoldt (talk | contribs)(diff) ← Previous revision | Latest revision (diff) | Newer revision → (diff)Beta blockers or beta-adrenergic blocking agents are certain drugs used to treat a variety of heart conditions and other diseases. They block the action of beta-type adrenergic receptors in the body. The hormone epinephrine (adrenaline) stimulates the sympathetic nervous system by acting on these receptors.
There are two types of beta receptors: beta 1 receptors located mainly in the heart, and beta 2 receptors located all over the body, but mainly in the lungs, muscles and arterioles.
If epinephrine acts on beta 1 receptors, the heart rate and the blood pressure increase, and the heart itself requires more oxygen. Drugs that block these beta 1 receptors therefore have the opposite effect: they lower the heart rate and blood pressure and are useful when the heart itself is deprived of oxygen. They are often prescribed after heart attacks.
Drugs that block beta 2 receptors generally have a relaxing effect and are prescribed for anxiety, migraine and alcohol withdrawal syndrome, among others.