Esmolol

Template:Short description Template:Drugbox Esmolol, sold under the brand name Brevibloc, is a cardio selective beta₁ receptor blocker with rapid onset,<ref name="pmid17235414">Template:Cite journal</ref> a very short duration of action, and no significant intrinsic sympathomimetic or membrane stabilising activity at therapeutic dosages.

It is a class II antiarrhythmic.<ref name="pmid2688391">Template:Cite journal</ref> 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.<ref>Template:Cite book</ref>

It was patented in 1980 and approved for medical use in 1987.<ref>Template:Cite book</ref>

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.<ref name="pmid29628593">Template:Cite journal</ref>

Pharmacology

Pharmacodynamics

Esmolol is a beta blocker, or an antagonist of the β-adrenergic receptors.<ref name="pmid33572109" /> It is selective for the β₁-adrenergic receptor and has no intrinsic sympathomimetic activity.<ref name="pmid33572109" />

Pharmacokinetics

Esmolol is considered a soft drug,<ref>Template:Cite journal</ref> 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-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.Template:Cn

Esmolol is classified as a beta blocker with moderate lipophilicity and hence moderate potential for crossing the blood–brain barrier.<ref name="Jankovic2014" /><ref name="pmid33572109">Template:Cite journal</ref> As such, esmolol may produce effects in the central nervous system and have a risk of neuropsychiatric side effects.<ref name="Jankovic2014" /><ref name="pmid33572109" />

Chemistry

The experimental log P is 1.7 and its predicted log P ranges from 1.82 to 2.02.<ref name="PubChem">Template:Cite web</ref><ref name="DrugBank">Template:Cite web</ref><ref name="ChemSpider">Template:Cite web</ref> It is a moderately lipophilic beta blocker.<ref name="Jankovic2014">Template:Cite journal</ref><ref name="Mannhold2005">Template:Cite journal</ref>