Esmolol

Esmolol (trade name Brevibloc) is a cardioselective beta₁ receptor blocker with rapid onset, a very short duration of action, and no significant intrinsic sympathomimetic or membrane stabilising activity at therapeutic dosages.

It is a class II antiarrhythmic. Esmolol decreases the force and rate of heart contractions by blocking beta-adrenergic receptors of the sympathetic nervous system, which are found in the heart and other organs of the body. Esmolol prevents the action of two naturally occurring substances: epinephrine and norepinephrine.

Dosing

Esmolol is given by slow intravenous injection. It is commonly used in patients during surgery to prevent or treat tachycardia, and is also used in treatment of acute supraventricular tachycardia. Esmolol is also the drug of choice when aortic dissection is suspected.

Metabolism

Esmolol is rapidly hydrolyzed by plasma esterases and not by plasma cholinesterases. Esmolol's short duration of action is based on the ester-methyl side chain which allows for quick hydrolysis. Esmolol's structure is reflected in its name, es-molol as in ester-methyl. Plasma cholinesterases and red cell membrane acetylcholinesterase do not have any action. This metabolism results in the formation of a free acid and methanol. The amount of methanol produced is similar to endogenous methanol production. Its elimination half-life is about 9 minutes.