Adrebloc

Indications

Esmolol Hydrochloride is a very short-acting beta-blocker given into a vein in hospital. It is used to quickly slow a fast heart rate in certain rhythm problems such as atrial fibrillation, atrial flutter and other supraventricular tachycardias, and to control a fast heart rate or high blood pressure during and after surgery.

How It Works

Esmolol blocks beta-1 receptors in the heart, the sites where adrenaline-like stress chemicals act. This slows the heart rate, reduces the force of each beat and lowers blood pressure. It is broken down in the blood within minutes, so its effect wears off quickly once the infusion is stopped, which lets doctors adjust it closely.

Dosage and Administration

Esmolol is given by a doctor or nurse as an intravenous injection and infusion, with continuous heart and blood pressure monitoring. The dose is worked out by body weight and adjusted to the response, as prescribed. It is not for use at home.

Interactions

• Calcium channel blockers such as Verapamil or Diltiazem, and Digoxin or Amiodarone: risk of very slow heart rate or heart block.
• Other blood pressure lowering medicines and anaesthetic agents: increased drop in blood pressure.
• Adrenaline: may be less effective, and blood pressure may rise sharply.
• Insulin and diabetes medicines: signs of low blood sugar such as a fast heartbeat may be hidden.

Contraindications

• Severe slow heart rate, sick sinus syndrome, or second or third degree heart block without a pacemaker.
• Cardiogenic shock or uncontrolled, decompensated heart failure.
• Pulmonary hypertension.
• Use of intravenous Verapamil or Diltiazem close to the time of Esmolol.
• Known allergy to Esmolol.

Side Effects

The most common side effect is low blood pressure, which can cause dizziness and sweating. Others include nausea, drowsiness, headache, slow heart rate and pain, redness or swelling at the injection site.

Because it is given in hospital, staff will watch for serious effects. Tell them immediately if you feel faint, have chest pain, sudden breathlessness or wheezing, or notice pain, blistering or skin damage where the drip is.

Pregnancy and Lactation

Esmolol may slow the baby's heart rate and lower the baby's blood sugar, especially near delivery. It is used in pregnancy only if the doctor judges it necessary. It is not known if it passes into breast milk; because it is short-acting and given in hospital, your doctor will advise on breastfeeding.

Precautions and Warnings

• Used with care in asthma or chronic lung disease, diabetes, kidney disease, and in people with circulation problems in the limbs.
• The concentrated solution must be diluted correctly; leakage outside the vein can damage tissue.
• Not for long-term control of heart rate; patients are usually switched to another medicine.

Overdose

Overdose can cause very low blood pressure, very slow heart rate, heart block, breathing problems and loss of consciousness. Stopping the infusion usually reverses effects quickly, and staff give supportive treatment as needed.

Therapeutic Class

Cardioselective beta-blocker, ultra short-acting (antiarrhythmic)

Storage

Hospital medicine: store as directed on the pack, usually below 30°C, away from light. Do not freeze.