Isoprenaline hydrochloride

How it works

It stimulates beta-1 and beta-2 adrenoceptors, increasing heart rate, atrioventricular conduction and myocardial contractility while causing peripheral and bronchial smooth-muscle relaxation.

Prescribing in practice

• It is a potent agent that should be given under continuous cardiac monitoring in a setting able to manage arrhythmias, as it can provoke serious ventricular arrhythmias and myocardial ischaemia.
• It is generally used as a short-term temporising measure for haemodynamically significant bradycardia or conduction block while definitive treatment such as pacing is arranged.
• Use with particular caution in patients with ischaemic heart disease, as the increase in heart rate and contractility raises myocardial oxygen demand.

Monitoring

Administer with continuous ECG and heart-rate monitoring and close observation of blood pressure and haemodynamic status.

Counselling the patient

• Explain to the team that this is a continuously monitored treatment for a dangerously slow heart rate.
• Palpitations, tremor and flushing are expected effects of the drug.
• It is usually a temporary measure until a more definitive treatment such as a pacemaker is in place.

Evidence & guidelines

Isoprenaline is an established option for temporary management of severe bradycardia and heart block, and resuscitation and peri-arrest guidance recognise its role pending pacing.