Esmolol; Indications/Uses, Dosage, Side effects, Drug Interaction ,Pregnancy

Esmolol

Esmolol is a cardioselective beta1 receptor blocker with rapid onset, a very short duration of action, and no significant intrinsic sympathomimetic or membrane stabilizing activity at therapeutic dosages. 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.

Esmolol is a cardioselective beta-blocker used in parenteral forms in the treatment of arrhythmias and severe hypertension. Esmolol has not been linked to instances of clinically apparent drug-induced liver injury.

Mechanism of Action of Esmolol

Similar to other beta-blockers, esmolol blocks the agonistic effect of the sympathetic neurotransmitters by competing for receptor binding sites. Because it predominantly blocks the beta-1 receptors in cardiac tissue, it is said to be cardioselective. In general, so-called cardioselective beta-blockers are relatively cardioselective; at lower doses they block beta-1 receptors only but begin to block beta-2 receptors as the dose increases. At therapeutic dosages, esmolol does not have intrinsic sympathomimetic activity (ISA) or membrane-stabilizing (quinidine-like) activity. Antiarrhythmic activity is due to blockade of adrenergic stimulation of cardiac pacemaker potentials. In the Vaughan Williams classification of antiarrhythmics, beta-blockers are considered to be class II agents.

Indications of Esmolol

  • High blood pressure
  • Postoperative hypertension
  • Nonvalvular atrial fibrillation
  • Atrial fibrillation
  • Atrial flutter
  • Intra- or Post-op SVT or hypertension
  • Supraventricular tachycardia
  • Intraoperative hypertension
  • Intraoperative tachycardia
  • Noncompensatory sinus tachycardia
  • Postoperative tachycardia
  • Also 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.

Contra-Indications of Esmolol

Hypersensitivity to the active substance or to any of the excipients or other beta-blockers (cross-sensitivity between beta-blockers is possible)

Dosage of Esmolol

Strengths: 10 mg/mL; 250 mg/mL; 20 mg/mL

Atrial Fibrillation

Recommended Dosing

  • (Step 1) Optional loading dose (500 mcg/kg IV over 1 minute), then 50 mcg/kg/min IV for 4 minutes; if the response is adequate, the infusion may be maintained at 50 mcg/kg/min; if the response is inadequate, see step 2.
  • (Step 2) Optional loading dose (500 mcg/kg IV over 1 minute) if necessary, then 100 mcg/kg/min IV for 4 minutes; if the response is adequate, the infusion may be maintained at 100 mcg/kg/min; if the response is inadequate, see step 3.
  • (Step 3) Optional loading dose (500 mcg/kg IV over 1 minute) if necessary, then 150 mcg/kg/min IV for 4 minutes; if the response is adequate, the infusion may be maintained at 150 mcg/kg/min; if the response is inadequate, see step 4.
  • (Step 4) If necessary, increase the dose to 200 mcg/kg/min IV
  • Maintenance dose: 25 to 200 mcg/kg/min IV
  • Maximum dose: 200 mcg/kg/min IV
  • Duration: Maintenance infusions may be continued for up to 48 hours

Atrial Flutter

Recommended Dosing

  • (Step 1) – Optional loading dose (500 mcg/kg IV over 1 minute), then 50 mcg/kg/min IV for 4 minutes; if the response is adequate, the infusion may be maintained at 50 mcg/kg/min; if the response is inadequate, see step 2.
  • (Step 2) – Optional loading dose (500 mcg/kg IV over 1 minute) if necessary, then 100 mcg/kg/min IV for 4 minutes; if the response is adequate, the infusion may be maintained at 100 mcg/kg/min; if the response is inadequate, see step 3.
  • (Step 3) – Optional loading dose (500 mcg/kg IV over 1 minute) if necessary, then 150 mcg/kg/min IV for 4 minutes; if the response is adequate, the infusion may be maintained at 150 mcg/kg/min; if the response is inadequate, see step 4.
  • (Step 4) – If necessary, increase the dose to 200 mcg/kg/min IV
  • Maintenance dose: 25 to 200 mcg/kg/min IV
  • Maximum dose: 200 mcg/kg/min IV
  • Duration: Maintenance infusions may be continued for up to 48 hours

Intra- or Post-op SVT or Hypertension

Immediate Control

  • Administer 1 mg/kg IV as a bolus dose over 30 seconds followed by 150 mcg/kg/min if needed
  • Adjust the infusion rate as required to maintain desired heart rate and blood pressure (refer to maximum recommended doses)

Gradual Control

  • Administer 500 mcg/kg IV as a bolus dose over 1 minute followed by a maintenance infusion of 50 mcg/kg/min IV for 4 minutes
  • Infusion may be continued at 50 mcg/kg/min or, if the response is inadequate, titrated upward in 50 mcg/kg/min increments (increased no more frequently than every 4 minutes) to a maximum of 300 mcg/kg/min; may administer an optional loading dose equal to the initial bolus (500 mcg/kg over 1 minute) prior to each increase in infusion rate

Maximum Recommended Doses

  • For the treatment of tachycardia, maintenance infusion dosages greater than 200 mcg/kg/min IV are not recommended; dosages greater than 200 mcg/kg/min IV provide little additional heart-rate-lowering effect and the rate of adverse reactions increases.
  • For the treatment of hypertension, higher maintenance infusion dosages (250 to 300 mcg/kg/min) may be required; the safety of doses above 300 mcg/kg/min has not been studied.

Side Effects of Esmolol

The most common 

More common

Rare

Drug Interactions of Esmolol

Esmolol  may interact with the following drug, supplements, & may change the efficacy of the drug

Pregnancy Catagory of Esmolol

FDA Pregnancy Category C 

Pregnancy

There are a limited amount of data from the use of esmolol hydrochloride in pregnant women. Studies in animals have shown reproductive toxicity .Based on the pharmacological action, in the later period of pregnancy, side effects on the foetus and neonate (especially hypoglycaemia, hypotension and bradycardia) should be taken into account.If treatment with Esmolol is considered necessary, the uteroplacental blood flow and foetal growth should be monitored. The new-born infant must be closely monitored.

Lactation

Esmolol hydrochloride should not be used during breast-feeding.It is not known whether esmolol hydrochloride/metabolites are excreted in human milk. A risk to the new-borns/infants cannot be excluded.

References