Esmolol, sold under the brand name Brevibloc, is a cardio selective
beta1 receptor blocker with rapid
onset
Onset may refer to:
*Onset (audio), the beginning of a musical note or sound
*Onset, Massachusetts
Onset is a census-designated place (CDP) in the town of Wareham, Massachusetts, United States. The population was 1,573 at the 2010 census.
Geog ...
,
a very short
duration of action
Pharmacodynamics (PD) is the study of the biochemical and physiologic effects of drugs (especially pharmaceutical drugs). The effects can include those manifested within animals (including humans), microorganisms, or combinations of organisms ( ...
, and no significant intrinsic
sympathomimetic or
membrane stabilising activity at therapeutic dosages.
It is a class II
antiarrhythmic
Antiarrhythmic agents, also known as cardiac dysrhythmia medications, are a group of pharmaceuticals that are used to suppress abnormally fast rhythms (Tachycardia, tachycardias), such as atrial fibrillation, supraventricular tachycardia and vent ...
.
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
The heart is a muscular organ in most animals. This organ pumps blood through the blood vessels of the circulatory system. The pumped blood carries oxygen and nutrients to the body, while carrying metabolic waste such as carbon dioxide to t ...
and other organs of the body. Esmolol prevents the action of two naturally occurring substances:
epinephrine and
norepinephrine
Norepinephrine (NE), also called noradrenaline (NA) or noradrenalin, is an organic chemical in the catecholamine family that functions in the brain and body as both a hormone and neurotransmitter. The name "noradrenaline" (from Latin '' ad' ...
.
It was patented in 1980 and approved for medical use in 1987.
Medical uses
To terminate
supraventricular tachycardia,
Episodic atrial fibrillation or flutter,
Arrhythmia during anaesthesia,
To reduce HR and BP during and after cardiac surgery, and
In early treatment of myocardial infarction.
Esmolol is also used in blunting the hemodynamic response to laryngoscopy and intubation.
Dosing
A loading dose of 0.5 mg/kg is given followed
by 0.05–0.2 mg/kg/min infusion.
Metabolism
Esmolol is considered a
soft drug,
one that is rapidly metabolized to an inactive form. Esmolol is rapidly metabolized by hydrolysis of the ester linkage, chiefly by the esterases in the cytosol of red blood cells and not by plasma cholinesterases or red cell membrane acetylcholinesterase. Total body clearance in man was found to be about 20 L/kg/hr, which is greater than cardiac output; thus the metabolism of esmolol is not limited by the rate of blood flow to metabolizing tissues such as the liver or affected by hepatic or renal blood flow. Esmolol's short duration of action is based on the
ester
In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides a ...
-
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. Esmolol has a rapid distribution half-life of about two minutes and an elimination half-life of about nine minutes.
References
External links
*
{{Portal bar , Medicine
Beta blockers
N-isopropyl-phenoxypropanolamines
Carboxylate esters
Diseases of the aorta
Methyl esters