Isoproterenol (Isoprenaline)

Indications

Isoproterenol (Isoprenaline) is used for: Adams-Stokes Attacks, Cardiac Arrest, Heart Block

Adult Dose

Intravenous Adams-Stokes Attacks, Cardiac Arrest, or Heart Block IV bolus: 0.02-0.06 mg (1-3 mL of a 1:50,000 dilution), initially, THEN doses of 0.01-0.2 mg IV infusion: 5 mcg/min (1.25 mL of a 1:250,000 dilution), initially, THEN doses of 2-20 mcg/min based on patient's response Shock 0.5-5 mcg/min (0.25-2.5 mL of a 1:250,000 dilution) IV infusion Bronchospasm During Anesthesia 0.01-0.02 mg IV repeat PRN

Child Dose

Renal Dose

Administration

IV/IM Administration Adminster by IV infusion (requires infusion pump), or By direct IV, IM, or SC injection In extreme emergencies, by intracardiac injection IV Preparation 1 mg (5 mL) in 500 mL D5W (2 mcg/mL) for IV infusion

Contra Indications

Angina pectoris; ventricular arrythmias requiring inotropic therapy; tachyarrhythmias; recent MI; tachycardia; heart block due to cardiac glycoside intoxication.

Precautions

Patient with CV disease (e.g. coronary artery disease, ischaemic heart disease), hypertension, diabetes mellitus, distributive shock, hyperthyroidism, aneurysms. May exacerbate Adams-Stokes seizures during normal sinus rhythm or transient heart block. Ensure adequate ventilation. Renal and hepatic impairment. Elderly. Pregnancy and lactation. Patient Counselling This drug may cause dizziness, if affected, do not drive or operate machinery. Monitoring Parameters Monitor blood pressure, heart rate, urine flow, ECG, central venous pressure, blood gases. Monitor acid-base balance and correct any electrolyte disturbances.

Pregnancy-Lactation

Pregnancy Category: C Lactation: not known if excreted into breast milk, avoid

Interactions

Enhanced arrhythmogenic effect with inhalational anaesthetics (e.g. halothane and cyclopropane). Antagonistic effects with β-adrenergic blocking agents (e.g. propranolol, atenolol). Increased risk of cardiac arrhythmias with levodopa. May reduce antianginal effects of nitrates. Magnified effect with MAOIs and chlorpromazine. Potentially Fatal: Severe arrhythmias with epinephrine and digitalis. Additive cardiotoxic properties and potential myocardial necrosis with IV methyl xanthines (e.g. aminophylline and theophylline) and IV corticosteroids.

Adverse Effects

Side effects of Isoproterenol (Isoprenaline) : Frequency Not Defined Tachycardia Hypertension Dysrhythmias Angina Dizziness Nervousness Restlessness Hypokalemia MI size increased Syncope Confusion Headache Tremor Nausea Vomiting Weakness, Tremor Dyspnea Pulmonary edema Diaphoresis Blurred vision

Mechanism of Action

Strong beta-1 & beta-2 effects resulting in relaxation of GI, bronchial, and uterine smooth muscle; may increase vasodilation of peripheral vasculature, and heart rate and contractility