Esmolol Hydrochloride (Brevibloc)

Anesthesia Implications

Classification: β1 Antagonist
Therapeutic Effects: Supraventricular tachycardia treatment, Antihypertensive, Negative Chronotropic
Time to Onset: 1-2 minutes
Time to Peak: 5 minutes
Duration: 10-20 minutes

Contraindications

Use with caution in patients with:
AV blocks, cardiac failure (not caused by tachycardia), COPD

Primary Considerations

Rapid onset/offset – Acutely reduces heart rate and blood pressure (through negative inotropic and chronotropic affects). Very effective at reducing/blunting sympathetic responses to intubation and surgical stimulation.

Reduces opioid requirements – large studies show that intraoperative infusions of esmolol reduce intraoperative and postoperative opioid requirements without a comparative change in pain scores.

High doses – the cardioselectivity of esmolol decreases with dose size. With higher doses, anticipate some B2 receptor antagonism (possibilities of brochial/smooth muscle constriction)

Hyperthyroid – Inhibits conversion of T4 to T3, which makes this a useful agent for hyperthyroid patients needing emergency surgery

Drug interaction – Esmolol is chemically incompatible with sodium bicarbonate. Morphine and warfarin will increase the bioavailability of esmolol. Esmolol increases the bioavailability of digoxin (increased risk of toxicity). Succinylcholine has a longer duration of action with esmolol. Nondepolarizing neuromuscular blockers may be proloned by esmolol.
Esmolol potentiates the myocardial depressive affects of IV drugs as well as volatile gases. The direct negative inotropic effects of ketamine may be pronounced when given with esmolol.

IV push dose

Hypertension: 25-100 mg (0.5-2 mg/kg). Repeat PRN every 5 minutes
Intubation Sympathetic response: Can be blunted with the above dose 2 minutes prior to laryngoscopy

IV infusion dose

Supraventricular Tachycardia:
Loading dose: 500 mcg/kg over 1 minute. Can repeat every 5 minutes PRN
50 – 200 mcg/kg/min. Titrate 25-50 mcg/kg/min.

Hypertension:
50-300 mcg/kg/min. Titrate 25-50 mcg/kg/min PRN

Bridge to another antihypertensive – Esmolol should be bridged to another antiarrythmic or antihypertensive once the blood pressure/heart rate is controlled and the infusion rate should be reduced by ~ 50% after doing so. The goal should be to discontinue esmolol after the second dose of the alternative.

Preparation: 5 grams of esmolol is mixed with 500 mL of D5W. This makes a concentration of 10 mg/mL

Reversal

If myocardial depression is excessive:
Atropine (1-2 mg), IV glucagon (1-5 mg), or a pacemaker may be utilized

Method of Action

Cardioselective Beta blocker. This is a way of saying that the esmolol targets B1 receptors (lowers heart rate). Higher doses reduce cardioselectivity (B2 will start to be blocked)

Metabolism

Hydrolysis via nonspecific esterases in red blood cell cytosol