Isoprenaline Hydrochloride for paediatric complete heart block

Background:

• Isoprenaline is a non-selective β-adrenoceptor agonist. 
• At cardiac β1 receptors, Isoprenaline has positive inotropic and chronotropic effects.  This increases cardiac output and heart rate.
• At β2 receptors, Isoprenaline causes systemic and pulmonary arterial vasodilation.  This leads to a reduction in systemic vascular resistance and bronchodilation.¹

Preparations:

Isoprenaline Hydrochloride Injection 1mg/5ml

Dose:

IV Infusion Dose for Complete Heart Block²:

IV Infusion: 0.1-1micrograms/Kg/minute
Infusion rate to be titrated according to clinical response.  Dose may be increased every 2-3 minutes until appropriate response obtained as directed by Consultant Cardiologist.

Route of administration³:

Continuous intravenous infusion, preferably via a central line. 
Isoprenaline has a low PH and may cause venous irritation and tissue damage in cases of extravasation. 
If a central line is not available, administer via a large peripheral vein.

Dilution³:

Diluent : Glucose 5% (preferred) or Nacl 0.9%

Peripheral line: Add 1mg (5mls) Isoprenaline hydrochloride to 45mls of diluent to make a final concentration of 1mg/50ml (20micrograms/ml)

If requiring doses greater than 25mls/hour:

Prepare an infusion of 10mg Isoprenaline hydrochloride in 500mls diluent

• Withdraw 50mls from the 500ml bag of diluent.
• Add 10mg (50mls) of Isoprenaline hydrochloride to make a final concentration of 10mg/500mls (20micrograms/ml).

Central line: Add 3mg (15ml) Isoprenaline to 35mls of diluent to make a final concentration of 3mg/50ml (60micrograms/ml)

If requiring doses greater than 25mls/hour:

Prepare an infusion of 30mg (150mls) Isoprenaline hydrochloride in 350mls diluent

• Withdraw 150mls from the 500ml bag of diluent.
• Add 30mg (150mls) of Isoprenaline hydrochloride to make a final concentration of 30mg/500mls (60micrograms/ml).

To calculate infusion rate: