esmolol hydrochloride

Action

Blocks stimulation of beta-adrenergic receptors (primarily beta₁ receptors), thereby reducing atrioventricular conduction and cardiac output and decreasing blood pressure

Availability

Injection: 10 mg/ml

Indications and dosages

➣ Supraventricular tachycardia

Adults: Initially, a loading dose of 500 mcg/kg/minute by I.V. infusion over 1 minute, followed by a maintenance infusion of 50 mcg/kg/minute over 4 minutes. If desired response doesn't occur after 5 minutes, repeat loading dose and increase maintenance infusion to 100 mcg/kg/minute for 4 minutes. Repeat sequence as needed, with maintenance dosage increased in increments of 50 mcg/kg/minute, to a maximum maintenance infusion of 200 mcg/kg/minute for 48 hours.

➣ Sinus tachycardia or hypertension

Adults: Initially, 80 mg (1 mg/kg) by I.V. bolus over 30 seconds; then, if needed, 150 mcg/kg/minute by I.V. infusion, to a maximum of 300 mcg/kg/minute

Off-label uses

• Acute myocardial ischemia

Contraindications

• Hypersensitivity to drug

• Heart failure

• Heart block greater than third degree

• Sinus bradycardia

• Cardiogenic shock

Precautions

Use cautiously in:

• renal impairment, diabetes, bronchospasm, cardiac disease, cerebrovascular insufficiency, peripheral vascular disease, hyperthyroidism, myasthenic conditions

• pregnant or breastfeeding patients.

Administration

• Be aware that compatible solutions include 5% dextrose for injection, 5% dextrose in lactated Ringer's injection, 5% dextrose in Ringer's injection, 5% dextrose in 0.45% or 0.9% sodium chloride injection, and lactated Ringer's injection.

• Don't mix with 5% sodium bicarbonate injection.

• Large fluid volumes may be needed to infuse drug. Use caution when excessive fluids could be harmful.

Adverse reactions

CNS: anxiety, depression, dizziness, drowsiness, headache, agitation, fatigue, confusion, speech disorders, asthenia

CV: peripheral ischemia, chest pain, bradycardia, hypotension

GI: nausea, vomiting, heartburn

GU: urinary retention

Respiratory: wheezing, dyspnea

Skin: flushing, pallor, erythema

Other: altered taste, fever, chills, edema, midscapular pain, inflammation or induration at infusion site

Interactions

Drug-drug. Alpha₁-adrenergic blockers: exaggerated antihypertensive effect

Catecholamines, reserpine: increased bradycardia and hypotension

Digoxin: increased digoxin blood level

Morphine: increased esmolol blood level

Succinylcholine: prolonged neuromuscular blockade

Drug-herbs. Ephedra (ma huang), St. John's wort, yohimbe: decreased anti-hypertensive effect

Patient monitoring

• Monitor vital signs and ECG, particularly for hypotension.

• Assess neurologic status, and institute safety measures as needed.

• Monitor fluid intake and output, watching for urinary retention.

• Check I.V. site regularly.

Patient teaching

• Explain to patient that drug is an emergency measure to control blood pressure, arrhythmias, or heart rate.

• Ensure patient he'll be closely monitored throughout drug therapy.

• Tell patient to report pain or redness at I.V. site.

• As appropriate, review all other significant adverse reactions and interactions, especially those related to the drugs and herbs mentioned above.