Esmolol

Absorption

Rapidly absorbed, steady-state blood levels for dosages from 50-300 μg/kg/min (0.05-0.3 mg/kg/mm) are obtained within five minutes.

Toxicity

Symptoms of overdose include cardiac arrest, bradycardia, hypotension, electromechanical dissociation and loss of consciousness.

Originator

Esmolol,AroKor Holdings

The Uses of Esmolol

Esmolol is a cardioselective beta1 receptor blocking agent.

The Uses of Esmolol

Agricultural chemical.

Indications

For the rapid control of ventricular rate in patients with atrial fibrillation or atrial flutter in perioperative, postoperative, or other emergent circumstances where short term control of ventricular rate with a short-acting agent is desirable. Also used in noncompensatory sinus tachycardia where the rapid heart rate requires specific intervention.

Background

Esmolol, commonly marketed under the trade name Brevibloc, is a cardioselective beta-1 receptor blocker. It has a rapid onset but short duration of action without causing significant intrinsic sympathomimetic or membrane stabilizing activities at recommended therapeutic doses. It works by blocking beta-adrenergic receptors in the heart, which leads to decreased force and rate of heart contractions. Esmolol prevents the action of two naturally occurring substances: epinephrine and norepinephrine.
The FDA withdrew its approval for the use of all parenteral dosage form drug products containing esmolol hydrochloride that supply 250 milligrams/milliliter of concentrated esmolol per 10-milliliter ampule. Other esmolol formulations are still available for use.

What are the applications of Application

Esmolol is a cardioselective beta1 receptor blocking agent

Definition

ChEBI: Methyl 3-{4-[2-hydroxy-3-(propan-2-ylamino)propoxy]phenyl}propanoate is a methyl ester that is methyl 3-(4-hydroxyphenyl)propanoate in which the hydrogen attached to the phenolic hydroxy group is substituted by a 2-hydroxy-3-(isopropylamino)propyl group. It is an aromatic ether, a member of ethanolamines, a methyl ester, a secondary alcohol and a secondary amino compound. It is functionally related to a 3-{4-[2-hydroxy-3-(propan-2-ylamino)propoxy]phenyl}propanoic acid.

Manufacturing Process

A solution of 17 g (0.1 mole) of 3-(4-hydroxyphenyl)propionic acid in 500 mL methanol and 2 mL concentrated sulfuric acid were placed in a Soxhlet extractor charged with 3A molecular sieves. The solution was refluxed for 72 hours and the sieve were exchanged at 24 hour intervals. The reaction medium was then evaporated to an oil which was dissolved in 100 mL toluene and extracted with 100 mL water (3 times). The toluene phase was dried over magnesium sulfate, treated with activated charcoal and evaporated to provide 15 g (80%) of a clear oil. The NMR spectrum was consistent with the methyl 3-(4-hydroxyphenyl)propionate.
The oil described above was utilized directly in the condensation reaction with the epichlorohydrin. A mixture of 0.1 mole of methyl 3-(4- hydroxyphenyl)propionate, 0.2 mole potassium carbonate and 0.4 mole epichlorohydrin in 250 mL acetone was heated to reflux for 24 hours. The reaction medium was then filtered and evaporated. The residue was taken up in 100 mL toluene and washed with 100 mL 1.0 N NaOH and 100 mL water (2 times). The toluene phase was then dried over magnesium sulfate and evaporated to provide the crude product as an oil. Purification was effected by vacuum distillation (156°C/0.4 mm) and provided methyl 3-[4-(2,3- epoxypropoxy)phenyl]propionate. The NMR and IR spectra and elemental analysis data were consistent with the assigned structure.
A mixture of 50 g (0.21 mole) of methyl 3-[4-(2,3- epoxypropoxy)phenyl]propionate and 100 mL of isopropylamine in 100 mLmethanol was heated to reflux for 4 hours. The reaction medium was then evaporated and the resulting oil taken up in methanol and treated with ethereal HCl and provided crystals which were recrystallized in similar fashion to provide 28 g (47%) of white crystals: melting point 85-86°C. The NMR and IR spectra and the elemental analysis data were consistent with the structure of methyl 4-(2-hydroxy-3-((1-methylethyl)amino)propoxy)benzenepropanoate.
In practice it is usually used as hydrochloride.

Therapeutic Function

Beta-adrenergic blocker

Hazard

A reproductive hazard.

Clinical Use

Esmolol (Brevibloc) is a short-acting intravenously administered β1-selective adrenoceptor blocking agent. It does not possess membrane-stabilizing activity or sympathomimetic activity.
Esmolol is used in the treatment of supraventricular tachyarrhythmias for rapid control of ventricular rate and reduction of myocardial oxygen consumption. Discontinuation of administration is followed by a rapid reversal of its pharmacological effects because of esmolol’s rapid hydrolysis by plasma esterases.

Side Effects

The most frequently reported adverse effects are hypotension, nausea, dizziness, headache, and dyspnea.As with many β-blocking drugs, esmolol is contraindicated in patients with overt heart failure and those in cardiogenic shock.

Metabolism

Esmolol undergoes rapid hydrolysis of ester linkage which is catalyzed by esterases found in the cytosol of red blood cells (RBCs). The plasma cholinersterases or RBC membrane acetylcholinesterases are not involved in this metabolic reaction. Metabolism of the drug occurs mainly in RBCs to form a free acid metabolite (with 1/1500 the activity of esmolol) and methanol.

Metabolism

The -blocker esmolol (Brevibloc) is unusual in that it is very rapidly metabolized; its plasma half-life is only 9 minutes. It is subject to hydrolysis by cytosolic esterases in red blood cells to yield methanol and an acid metabolite, the latter having an elimination half-life of about 4 hours. Only 2% of the administered esmolol is excreted unchanged. Because of its rapid onset and short duration of action, esmolol is used by the intravenous route for the control of ventricular arrhythmias in emergencies.