Esmolol for

Tabbutt S, Nicolson SC, Adamson PC, Zhang X, Hofhnan ML, Wells W, Backer CL, McGowan FX, Tweddell JS, Bokesch P, Schreiner M. The safety, efficacy, and pharmacokinetics of esmolol for blood pressure control immediately after repair of coarctation of the aorta in infants and... 

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). 

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. 

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. 

In turn, a- and )3-adrenoblockers are subdivided into selective and nonselective groups. Nonselective 8-adrenoblockers exhibit affinity for both and Sj-adrenoreceptors. Included in this category are propranolol, nadolol, timolol, and labetalol (a combined a- and )3-adrenoblocker). Selective jS -blockers are acebutol, atenolol, esmolol, and meto-prolol, which in therapeutic doses predominantly binds to jS -adrenoreceptor regions. 

Reduce the dosage of esmolol as follows 30 minutes after the first dose of the alternative agent, reduce esmolol infusion rate by 50%. Following the second dose of the alternative agent, monitor patient s response and, if satisfactory control is maintained for the first hour, discontinue esmolol infusion. 

Withdrawal effects - The use of esmolol infusions for up to 24 hours has been well documented. Limited data indicate that esmolol is well tolerated for up to 48 hours. 

Compatibility/Stability- Esmolol, at a final concentration of 10 mg/mL, is compatible with the following solutions and is stable for 24 hours or more at controlled room temperature or under refrigeration 5% dextrose injection 5% dextrose in Lactated Ringer s injection 5% dextrose in Ringer s injection 5% dextrose and 0.9% or 0.45% sodium chloride injection Lactated Ringer s injection potassium chloride (40 mEq/L) in 5% dextrose injection 0.9% or 0.45% sodium chloride injection. 

In the first 2 weeks post-MI, caution is advised and careful dose titration is especially important, particularly in patients with markedly impaired ventricular function. Intraoperative and postoperative tachycardia and hypertension Do not use esmolol as the treatment for hypertension in patients in whom the increased blood pressure is primarily caused by the vasoconstriction associated with hypothermia. Renal/Hepatic function impairment Use with caution. 

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 es-molol s rapid hydrolysis by plasma esterases. 

Class II drugs are the p-adrenoceptor antagonists that suppress the sympathetic modulation of the heart action. They are used in the therapy of sinus tachycardia, supraventricular paroxysmal tachycardia and ventricular extra-systoles. Because of its rapid onset and short duration of action, esmolol is the preferred drug in this class for intra-operative use. 

Esmolol is a -selective blocker that is rapidly metabolized via hydrolysis by red blood cell esterases. It has a short half-life (9-10 minutes) and is administered by constant intravenous infusion. Esmolol is generally administered as a loading dose (0.5-1 mg/kg), followed by a constant infusion. The infusion is typically started at 50-150 mcg/kg/min, and the dose increased every 5 minutes, up to 300 mcg/kg/min, as needed to achieve the desired therapeutic effect. Esmolol is used for management of intraoperative and postoperative hypertension, and sometimes for hypertensive emergencies, particularly when hypertension is associated with tachycardia. 

Esmolol is a short-acting 3 blocker used primarily as an antiarrhythmic drug for intraoperative and other acute arrhythmias. See Chapter 10 for more information. Sotalol is a nonselective 3-blocking drug that prolongs the action potential (class 3 action). 

Esmolol Short-acting, IV only used for intraoperative and other acute arrhythmias ... 

General supportive care should be provided. Aggressive gut decontamination should be carried out using repeated doses of activated charcoal and whole bowel irrigation. Propranolol or other blockers (eg, esmolol) are useful antidotes for B-mediated hypotension and tachycardia. Phenobarbital is preferred over phenytoin for convulsions most anticonvulsants are ineffective. Hemodialysis is indicated for serum concentrations greater than 100 mg/L and for intractable seizures in patients with lower levels. 

Endogenous norepinephrine stimulates cardiac beta receptors. Receptor-linked cAMP-dependent protein kinases phosphorylate calcium channels to increase intracellular calcium. Elevated intracellular calcium increases conduction velocity (phase 0) and decreases the threshold potential in normal SA and AV node cells (see Figure 12.13). Beta blockers slow spontaneous conduction velocity in the SA node by approximately 10-20 percent. In addition, beta blockers can slow conduction velocity while increasing the refractory period of the AV node. These effects control the ventricular rate in atrial fibrillation or flutter and terminate paroxysmal supraventricular tachycardias. They are also safer, although somewhat less effective, than other drugs for suppression of premature ventricular complexes (PVCs). Drugs in this class approved by the FDA for treatment of various arrhythmias include propranolol, acebutolol, and esmolol. Problems with the beta blockers include drowsiness, fatigue, impotence, and depressed ventricular performance. 

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