Esmolol dosing

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 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. 

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. 

Compounds that exhibit roughly the same affinity to and j32 rsceptors independent of dosage such as nadolol, propranolol, pindolol, timolol, and labetalol (combined a- and j3-adrenoblocker) are classified as nonselective blockers. Drugs which in therapeutic doses have higher affinity to -receptors than to j32-receptors such as acebutol, atenolol, metoprolol, and esmolol, are called selective or cardioselective j3-adrenoblockers. 

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. 

Intraoperative and postoperative tachycardia and hypertension - In the intraoperative and postoperative settings, it is not always advisable to slowly titrate the dose of esmolol to a therapeutic effect. Therefore, 2 dosing options are presented Immediate control dosing and a gradual control when the physician has time to titrate. 

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 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. 

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. 

Pharmacokinetics. For long-term use, any of the oral preparations of P-blocker is suitable. In emergencies, esmolol may be given i.v. (see Table 24.1). Esmolol has a t) of 9 min, which justifies adininistration by infusion with rapid alterations in dose, possibly titrated against response. 

Followed 5 min later by a second 5 mg IV dose and then 50-100 mg PO every day initiated 1 to 2 h after the intravenous dose Alternatively, initial intravenous therapy may be omitted Esmolol... 

The onset and cessation of P-receptor blockade with esmolol are rapid peak hemodynamic effects occur within 6 to 10 minutes of administration of a loading dose, and there is substantial attenuation of P-blockade within 20 minutes of stopping an infusion. Esmolol may have striking hypotensive effects in normal subjects, although the mechanism of this effect is unclear. 

B. Specific drugs and antidotes. Beta blockers effectively reverse cardiotoxic effects mediated by excessive beta-adrenergic stimulation. Treat tachyarrhythmias or hypotension with intravenous propranolol, 0.01-0.02 mg/kg (see p 496), or esmolol, 0.025-0.1 mg/kg/min (p 443), beginning with low doses and titrating to effect. Because of its short half-life and cardioselectivity, esmolol is preferred. 

I. Pharmacology. Esmolol is a short-acting, IV, cardioselective beta-adrenergic blocker with no intrinsic sympathomimetic or membrane-depressant activity. In usual therapeutic doses, it causes little or no bronohospasm in patients with asthma. Esmolol produces peak effects within 6-10 minutes of administration of an intravenous bolus. It is rapidly hydrolyzed by red blood cell esterases, with an elimination half-life of 9 minutes therapeutic and adverse effects disappear within 30 minutes after the infusion is discontinued. 

Several studies have similarly found that the use of esmolol reduced the required dose of isoflurane or propofol, or resulted in a deeper anaesthesia (as measured by BIS), but only in the presence of an opioid. " As there appears to be no pharmacokinetic interaction between esmolol and propofol it has been suggested that esmolol could be interacting with the opioid. ... 

However, in one study 60 patients were given one of three treatments before induction of anaesthesia with propofol esmolol 1 mg/kg followed by an infusion of250 micrograms/kg per minute midazolam or placebo (sodium chloride 0.9%). No opioids were given. Esmolol and midazolam reduced the required induction doses of propofol by 25% and 45%, respectively. Esmolol reduced the mean heart rate by 7.6 bpm compared with placebo in the pre-induction period, and the only adverse effect noted was a transient episode of bradycardia (44 bpm) in one patient receiving esmolol. Esmolol reduces cardiac output by reduction of heart rate and stroke volume and this possibly reduces the required induction dose of propofol by changing its distribution."... 

Another study found that a single 80-mg dose of esmolol after induction of anaesthesia with propofol and either fentanyl or placebo did not affect the depth of anaesthesia (measured by BIS) in either group of patients, even though cardiovascular effects were seen (reduction in systolic arterial pressure and heart late). ... 

B. Several studies suggest that beta blockers, such as atenolol and esmolol, given before induction reduce the anaesthetic dose requirement and may potentiate hypnosis. However, there are concerns that reducing the dose of anaesthetic may increase the risk of intra-operative awareness and it has been suggested that the use of BIS to predict the depth of anaesthesia in the presence ofbeta blockers may not be valid.There is a possibility that acute as well as chronic administration ofbeta blockers may prevent perioperative cardiac complications, but more study is needed on this. ... 

Wilson ES, McKinlay S, Crawford JM, Robb HM, The influence of esmolol on the dose of propofol required for induction of anaesthesia. Anaesthesia (2004) 59,122-6,... 

Berkenstadt H, Loebstein R, Faibishenko I, Halkin H, Keidan I, Perel A, Effect of a single dose of esmolol on the bispectral index scale (BIS) during propofol/fentanyl anaesthesia, Br JAnaesth (2002) 89, 509-11,... 

In 6 patients stabilised on warfarin, acebutolol 300 mg three times daily for 3 days had no effect on prothrombin time response. Similarly, in one patient taking warfarin, neither atenolol 100 mg daily nor metoprolol 100 mg twice daily for 3 weeks had any effect on prothrombin time. Similarly, in studies in healthy subjects the following beta blockers had no clinically relevant effects on the pharmacokinetics and/or anticoagulant response to warfarin atenolol 100 mg daily, betaxolol 20 mg daily, bisoprolol 10 mg daily, esmolol, or metoprolol 100 mg twice daily. In contrast, the minimum steady state plasma warfarin levels of 6 healthy subjects rose by 15% when they took propranolol 80 mg twice daily in one study." Similarly, in another study in 6 healthy subjects given propranolol 80 mg twice daily for 7 days with a single dose of warfarin on day 4, the AUC of warfarin was increased by 16.3% and the in maximum serum level was increased by 23%, but there was no change in the prothrombin time. A patient stabilised on warfarin had a rise in his Brit-... 

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