Non-selective β-agonist Pregnancy: Isoprenaline has often been administered during pregnancy; animal tests have shown no teratogenic effect and over 30 years of clinical experience has not revealed teratogenic effects. As with any medication in pregnancy, weigh clinical benefit against possible risk to mother and child. Administration during breast-feeding is not recommended. No human fertility data.

Isoprenaline hydrochloride

Isoprenaline is a non-selective beta-adrenoceptor agonist (sympathomimetic) used as a specialist treatment for severe symptomatic bradycardia and heart block, typically as a temporising measure pending pacing.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: Start at 0.01 microgram/kg/minute; increase in increments of 0.01 microgram/kg/minute up to a maximal dose of 0.15 microgram/kg/minute

Route: Intravenous infusion

Frequency: Continuous infusion, carefully titrated under close monitoring to the lowest possible dose that obtains a heart rate of 50-60 beats per minute; rate adjusted according to the patient's heart rate

Max: 0.15 microgram/kg/minute

Must only be administered by physicians trained in anaesthesia, cardiology or intensive care, in an appropriately monitored or critical care setting; circulatory and respiratory functions should be closely monitored. Isoprenaline should not be used routinely. Dilution (per SPC): dilute 10 ml of concentrate (= 2.0 mg) in 500 ml sodium chloride 9 mg/ml (0.9%) or glucose 50 mg/ml (5%), giving a 4 microgram/ml infusion solution. Do NOT inject at the same time as adrenaline under any circumstances; if both are necessary they can be given alternately every 4 hours. ECG monitoring required, with dose reduction in ventricular myocardial hyperexcitability (polymorphic extrasystoles, repetitive bursts pacing or ventricular tachycardia). Caution if doses are sufficient to reach a heart rate greater than 130 beats per minute. No paediatric posology is stated in this SPC.

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

Hypersensitivity to the active substance or to any of the excipients
Concomitant use with adrenaline
Pre-existing ventricular arrhythmias
Tachyarrhythmias
Cardiac glycoside intoxication
Myocardial infarction
Angina pectoris

Side effects

Fast heartbeat (tachycardia)
Arrhythmia
Precordial pain
Low blood pressure / high blood pressure
Nervousness, shakiness, dizziness, headache
Nausea
Asthenia

Interactions

Adrenaline — must not be administered at the same time (may be given alternately every 4 hours if both are necessary); may be used simultaneously with dopamine or phenylephrine
Digitalis — contraindicated in digitalis intoxication
Halogenated anaesthetics (chloroform, cyclopropane, halothane) — may cause or worsen ventricular arrhythmia
MAOIs — should not be administered simultaneously; with doxapram, risk of severe hypertension
Other cardiotonics or CNS stimulants (sympathomimetics, theophylline, thyroid hormone products) — increased isoprenaline toxicity
Tricyclic antidepressants (e.g. imipramine) — cardiovascular side effects may be worsened
Ergotamine — increased risk of ergotism; sympathomimetic vasoconstrictors (e.g. oxytocin) — hypertension

Clinical monograph

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.

Reference: UK Resus Council; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Pathways