Isoprenaline information from DrugsUpdate  

Pharmacodynamics

Pharmacokinetics

Isoprenaline is a sympathomimetic that acts directly on β-adrenergic receptors. It stimulates the CNS, has powerful stimulating action on the heart, and has bronchodilating properties.

Duration
Inhalation: About 2 hours.

Absorption
Less active after oral admin than after parenteral admin due to sulfate conjugation in the gut. Also absorbed through the oral mucosa.

Metabolism
Resistant to metabolism by monoamine oxidase. Metabolised by catechol-O-methyltransferase in the liver, lungs, and other tissues.

Excretion
Via urine (as unchanged drug and metabolites). Plasma half-life: IV: 1 to several min depending on rate of injection.

Oral
More extended initial half-life. Inhalation: 5 minutes.

Isoprenaline Indications / Isoprenaline Uses

Information Not Available

Isoprenaline Adverse Reactions / Isoprenaline Side Effects

Nervousness, restlessness, insomnia, anxiety, tension, blurring of vision, fear, excitement. Rarely, sweating, weakness, pallor, dizziness, mild tremor, headache, flushing of the face or skin, nausea, vomiting, tinnitus, lightheadedness, asthenia. Swelling of the parotid glands (prolonged use). Pulmonary oedema, dyspneoa. Palpitation and ventricular tachycardia. Transient myocardial ischaemia or myocardial dysfunction in children.

Potentially Fatal: Ventricular arrhythmias.

Precautions

Information Not Available

Special Precautions

Coronary artery disease, coronary insufficiency, diabetes, hyperthyroidism. Pregnancy and lactation. Parenteral: May paradoxically worsen heart block or precipitate Adams-Stokes attacks during normal sinus rhythm or transient heart block. Doses which can increase heart rate to >130 beats/min may increase the risk of inducing ventricular arrhythmias; caution in patients with failing heart or in those with significant degree of arteriosclerosis. Monitor response to therapy by frequent determination of the central venous pressure and blood gases. Ensure adequate ventilation. Monitor acid-base balance and correct any electrolyte disturbances. Inhalation: Severe paradoxical airway resistance may occur with repeated and excessive use. Carefully instruct the patient in the proper technique of admin.

Other Drug Interactions

Additive peripheral vasoconstriction may occur with ergot alkaloids. Cardiac, bronchodilating and vasodilating effects may be antagonised by β-blockers e.g. propranolol.

Potentially Fatal: IV: Severe arrhythmias may occur with epinephrine, digitalis, cyclopropane, halogenated hydrocarbon anaesthetics.

Other Interactions

Information Not Available

Dosage

Intravenous
Bronchospasm during anaesthesia
Adult: 0.01-0.02 mg (0.5-1 ml of a 1:50,000 dilution), repeat when necessary.
Elderly: Lower doses may be required.

Intravenous
Emergency treatment of cardiac arrhythmias
Adult: IV bolus injection: Initially, 0.02-0.06 mg (1-3 ml of a 1:50,000 dilution). Subsequent dose range: 0.01-0.2 mg. IV infusion: Initially, 5 mcg/minute. Adjust subsequent doses based on patient's response; usual range: 2-20 mcg/minute.
Child: Initially, 0.1 mcg/kg/minute. Subsequent dose range: 0.1-1 mcg/kg/minute.

Intravenous
For temporary use in 3rd degree atrioventricular block until pacemaker insertion
Adult: 2-10 mcg/minute via IV infusion. Adjust subsequent rate based on patient's heart rate and rhythm response.

Intravenous
Complete heart block following closure of ventricular septal defects
Adult: 0.04-0.06 mg (2-3 mL of a 1:50,000 dilution) as bolus doses.
Child: Infants: 0.01-0.03 mg (0.5-1.5 mL of a 1:50,000 dilution) as bolus dose.

Intravenous
Adjunct in shock
Adult: 0.5-5 mcg/minute, adjust subsequent rate based on patient's response. In advanced stages: rates >30 mcg/minute have been used. Not recommended for >1 hr usage in patients with septic shock.

Intravenous
As a diagnostic agent
Adult: For diagnosing etiology of mitral regurgitation: 4 mcg/minute as infusion. For diagnosis of coronary artery disease or lesions: 1-3 mcg/minute as infusion.

Parenteral
Postoperative cardiac patients with bradycardia
Adult: For less urgent situations. Initial: 0.2 mg via IM or SC admin. Subsequent dose ranges: 0.02-1 mg (via IM admin) or 0.15-0.2 mg (via SC admin).
Child: 0.029 mcg/kg/minute via IV infusion.

Reconstitution
Reconstitute with supplied diluent only.

Food(before/after)

Information Not Available

Isoprenaline and Pregnancy

Caution when used during pregnancy

Category C: Either studies in animals have revealed adverse effects on the foetus (teratogenic or embryocidal or other) and there are no controlled studies in women or studies in women and animals are not available. Drugs should be given only if the potential benefit justifies the potential risk to the foetus.

Isoprenaline and Lactation

Caution when used during lactation

Isoprenaline and Children

Information Not Available

Isoprenaline and Geriatic

Information Not Available

Isoprenaline and Other Contraindications

Tachyarrhythmias; tachycardia or heart block due to digitalis intoxication; ventricular arrhythmias which require inotropic therapy; angina pectoris.

Storage

Intravenous
Store at controlled room temperature 20-25°C (68-77°F). Reconstituted solutions: To be used within 24 hours.

Parenteral
Store at controlled room temperature 20-25°C (68-77°F). Reconstituted solutions: To be used within 24 hours.

Lab interference

Intravenous
Store at controlled room temperature 20-25°C (68-77°F). Reconstituted solutions: To be used within 24 hours.

Parenteral
Store at controlled room temperature 20-25°C (68-77°F). Reconstituted solutions: To be used within 24 hours.