Esmolol

Esmolol. Esmolol hydrochloride, an ultrashort acting cardioselective P ceptor blocker having no ISA or membrane stabilizing activity, is... 

Esmolol is iv adrninistered. Maximal P-adrenoceptor blockade occurs in 1 min. Its elimination half-life is about 9 min. EuU recovery from P-adrenoceptor blockade is within 30 min after stopping the infusion. The therapeutic plasma concentrations are 0.4—1.2 lg/mL. It is metabolized by hydrolysis in whole blood by red blood cell esterases resulting in the formation of a primary acid metabohte and free methanol. The metabohte is pharmacologically inactive. The resulting methanol levels are not toxic. Esmolol is 55% bound to plasma protein, the acid metabohte only 10%. Less than 2% of parent dmg and the acid metabohte are excreted by the kidneys. Plasma levels may be elevated and elimination half-hves prolonged in patients with renal disease (41). 

Because of its brief half-life and minimal hpid solubihty, the side effects of esmolol are transient and include hypotension, cold extremities, dyspnea (from bronchospasms), bradycardia, nausea, vomiting, and headaches (41). 

Elestolol sulfate is a nonselective, ultrashort acting P-adrenoceptor blocker. It has no ISA and produces weak inhibition of the fast sodium channel. The dmg is under clinical investigation for supraventricular tachyarrhythmias, unstable angina, and acute MI. In humans, flestolol has hemodynamics and electrophysiologic effects similar to those of other P-adrenoceptor blockers. The pharmacokinetics of flestolol are similar to those of esmolol. It is 50 times more potent than esmolol and the elimination half-life is 7.2 min. Recovery from P-adrenoceptor blockade is 30—45 min after stopping iv infusions. The dmg is hydrolyzed by tissue esterases and no active metabohtes of flestolol have been identified (41). 

Class II drugs are classical (3-adrenoceptor antagonists such as propranolol, atenolol, metoprolol or the short-acting substance esmolol. These drugs reduce sinus rate, exert negative inotropic effects and slow atrioventricular conduction. Automaticity, membrane responsiveness and effective refractory period of Purkinje fibres are also reduced. The typical extracardiac side effects are due to (3-adrenoceptor blockade in other organs and include bronchospasm, hypoglycemia, increase in peripheral vascular resistance, depressions, nausea and impotence. 

Class II antiarrhythmic drugs include beta (( -adrenergic blocking drugs, such as acebutolol (Sectral), esmolol (Brevibloc), and propranolol (Inderal). These drugp also decrease myocardial response to epinephrine and norepinephrine (adrenergic neurohormones) because of their ability to block stimulation of p receptors of the... 

Esmolol 10-20 minute <5 minute 2-21 meg /minute Conduction block, hypotension, bronchospasm Rapid onset, short half-life... 

Propranolol 0.5-1 mg slow intravenous push (IVP) up to a total of 5 mg, then 20-80 mg enterally q6h ° Esmolol may be utilized if a rapid short-acting agent is needed... 

Esmolol hydrochloride 250-500 mcg/kg/minute IV bolus, then 50-100 mcg/kg/minute by infusion may repeat bolus after 5 minutes or increase infusion to 300 mcg/minute 1-2 minutes 10-30 minutes Hypotension, nausea, asthma, first-degree heart block, heart failure Aortic dissection, perioperative... 

Alternatively, initial intravenous therapy can be omitted Esmolol... 

P-Blockersa Inhibit AV nodal conduction by slowing AV nodal conduction and prolonging AV nodal refractoriness Esmolol 500 mcg/kg IV over 1 minute Propranolol 0.15 mg/kg IV Metoprolol 2.5-5 mg IV x 2-3 doses Esmolol 50-200 mcg/kg/minute continuous infusion Propranolol 80-240 mg/day Metoprolol 50-200 mg/day ... 

Esmolol Hypotension, sinus bradycardia, AV block, heart failure exacerbation... 

Esmolol hydrochloride is a competitive p-adrenergic receptor antagonist it is selective for pT adrenoceptors. In contrast to pindolol, esmolol has little intrinsic sympathomimetic activity, and it differs from propranolol in that it lacks membrane stabilizing activity Of all of the p-adrenergic blocking drugs, this compound has the shortest duration of action because it is an ester, it is hydrolyzed rapidly by plasma esterases and must be used by the intravenous route Esmolol is approved only for the treatment of supraventricular arrhythmias... 

Esmolol Starting maintenance dose of 0.1 mg/kg/min IV, with titration in increments of 0.05 mg/kg/min every 10 to 15 minutes as tolerated by BP until the desired therapeutic response is obtained, limiting symptoms develop, or a dose of 0.2 mg/kg/min is reached. An optional loading dose of 0.5 mg/kg may be given by slow IV administration (2 to 5 minutes) for more rapid onset of action. Alternatively, the initial IV therapy may be omitted. 

The most serious side effects early in ACS are hypotension, bradycardia, and heart block. Initial acute administration of //-blockers is not appropriate for patients presenting with decompensated heart failure. However, therapy may be attempted in most patients before hospital discharge after treatment of acute heart failure. Diabetes mellitus is not a contraindication to //-blocker use. If possible intolerance to //-blockers is a concern (e.g., due to chronic obstructive pulmonary disease), a short-acting drug such as metoprolol or esmolol should be administered IV initially. 

If patients are hemodynamicaUy stable, the focus should be directed toward control of ventricular rate. Drugs that slow conduction and increase refractoriness in the AV node should be used as initial therapy. In patients with normal LV function (left ventricular ejection fraction >40%), IV j3-blockers (propranolol, metoprolol, esmolol), diltiazem, or verapamil is recommended. If a high adrenergic state is the precipitating factor, IV /J-blockers can be highly effective and should be considered first. In patients with left ventricular ejection fraction <40%, IV diltiazem and verapamil... 

Antiadrenergic therapy with the short-acting agent esmolol is preferred because it can be used in patients with pulmonary disease or at risk for cardiac failure and because its effects can be rapidly reversed. 

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