User:Mr. Ibrahem/Beta blockers

Beta blockers (β-blockers) are a class of medication mainly used to manage abnormal heart rhythms, ischemic heart disease, and heart failure. They are also used to treat high blood pressure, though are no longer a first choice for initial treatment in most people. Other uses may include overactive thyroid, essential tremor, glaucoma, and migraines. Common agents in this class include atenolol, bisoprolol, carvedilol, and metoprolol. They can be taken by mouth, given intravenously, or used as eye drops.

Side effects may include tiredness, headache, trouble sleeping, nausea, and sexual dysfunction. They may cause complications in asthma, low blood pressure, and heart block. Lower doses may be required in those with liver problems and heart failure. They may also interact with certain calcium channel blockers. Beta blocker toxicity is associated with a high risk of a poor outcome.

Beta blockers work by binding to and blocking epinephrine (adrenaline) and norepinephrine (noradrenaline) from activating beta receptors, and thus decrease sympathetic nervous system activity. Some block activation at all β-adrenergic receptors while others are selective for β1- receptors. β1- receptors are located mainly in the heart and kidneys. β2-receptors are located in the smooth muscles of blood vessels and the airway. β3- receptors are located in fat cells.

The first medically useful beta blocker, propranolol, was made in 1964 by James Black. It is considered one of the most important contributions to pharmacology of the 20th century. Beta blockers are among the most widely used medications. Some are available as generic medication and are relatively inexpensive. Their use in particular sports is banned by the International Olympic Committee as they improve accuracy.