Sunday, May 20, 2012
Beta Blockers
Beta Blockers are drugs that slow the heart rate, decrease cardiac output, lessen the force with which the heart muscle contracts and reduce blood vessel contraction. They do this by blocking beta-adrenergic receptors in various parts of the body. This prevents adrenaline (epinephrine) from stimulating these receptors. They may be used to treat abnormal heart rhythms (arrhythmias) and prevent abnormally fast heart rate (tachycardia) or irregular rhythms such as premature ventricular beats. Since they reduce the demand of the heart muscle for oxygen they may be useful in treating angina (chest pain), which occurs when the oxygen demand of the heart exceeds the supply. They have become an important drug in improving survival after a person has had a heart attack. Beta-blockers are also used to treat high blood pressure and other heart conditions.
Beta-blockers reduce the heart rate, the heart's workload and the heart's output of blood, which lowers blood pressure. Beta-blockers cause contraction of the smooth muscle of the peripheral arteries and thereby decrease blood flow to body tissues. As a result, the patient may experience coolness in the hands and feet. In response to the beta-blockers, the airways are squeezed (constricted) by the contracting smooth muscle; this squeezing (impingement) on the airway causes wheezing, especially in individuals with a tendency for asthma.
The beta-blockers include:
- atenolol (Tenormin),
- propranolol (Inderal),
- metoprolol (Toprol),
- nadolol (Corgard),
- betaxolol (Kerlone),
- acebutolol (Sectral),
- pindolol (Visken),
- carvedilol (Coreg)
- penbutolol (Levatol),
- bisoprolol (Zebeta),
- Timolol (Blocadren).
Potential side effects of beta-blockers:
- Insomnia
- Cold hands and feet
- Tiredness or depression
- Slow heartbeat
- Symptoms of asthma
- Impotence may also occur
- If you have diabetes and you're taking insulin, have your responses to therapy monitored closely.
