What is the recommended dosage for isoprenaline (isoproterenol) infusion through a syringe pump?

Isoprenaline Infusion Dosing via Syringe Pump

For adults in shock, initiate isoprenaline at 0.5-5 mcg/min via continuous intravenous infusion, prepared by diluting 1 mg (5 mL) in 500 mL of 5% dextrose to yield a concentration of 2 mcg/mL. 1

Standard Adult Preparation and Dosing

• Dilute 1 mg of isoprenaline in 500 mL of 5% dextrose to create a concentration of 2 mcg/mL 1
• Start infusion at 0.5-5 mcg/min (0.25-2.5 mL/min of diluted solution) 1
• Concentrations up to 10 times greater (20 mcg/mL) may be used when volume restriction is essential 1
• In advanced shock states, rates exceeding 30 mcg/min have been utilized 1

Pediatric Dosing

For children, the American Heart Association recommends an initial infusion rate of 0.1 mcg/kg/min, with a usual therapeutic range of 0.1-1.0 mcg/kg/min. 1

• Begin at 0.1 mcg/kg/min and titrate based on clinical response 1
• The typical effective range spans 0.1-1.0 mcg/kg/min 1

Titration and Monitoring Parameters

Adjust infusion rate based on heart rate, central venous pressure, systemic blood pressure, and urine output. 1

• Decrease or temporarily discontinue if heart rate exceeds 110 beats per minute 1
• Monitor for cardiac arrhythmias and myocardial ischemia, particularly in patients with coronary artery disease or cardiomyopathy 1
• Titrate gradually upward from the lowest effective dose based on hemodynamic response 1

Critical Administration Considerations

• Inspect solution before use - discard if pinkish, darker than slightly yellow, or contains precipitate 1
• Use diluted solution immediately and discard any unused portion 1
• Isoprenaline contains sodium metabisulfite, which may cause allergic reactions including anaphylaxis in sulfite-sensitive patients 1

Important Contraindications

Do not use isoprenaline in patients with tachycardia, ventricular arrhythmias, or angina pectoris. 1

Drug Interactions to Avoid

• Never administer simultaneously with epinephrine - both are direct cardiac stimulants and combined use may induce serious arrhythmias 1
• Effects may be potentiated by tricyclic antidepressants, MAO inhibitors, levothyroxine, and certain antihistamines (chlorpheniramine, tripelennamine, diphenhydramine) - monitor hemodynamics closely and adjust doses accordingly 1
• Beta-blockers antagonize the cardiostimulating and bronchodilating effects of isoprenaline 1

Special Clinical Scenarios

For bronchospasm during anesthesia, administer as bolus injection rather than infusion: dilute 0.2 mg (1 mL) to 10 mL with normal saline or 5% dextrose, then give 10-20 mcg (0.5-1 mL of diluted solution) as initial dose, repeatable as needed 1

In Brugada syndrome with repetitive ventricular arrhythmias, a bolus of 1-2 mcg followed by continuous infusion at 0.15 mcg/min has been effective for suppressing arrhythmic storm 2