FFinalistSouthampton · 2027
The drug atlas
Cardiovascular/Inotrope / vasopressor & peri-arrest

Inotropes, vasopressors & bradycardia drugs

also: adrenaline · noradrenaline · atropine · dobutamine · glucagon

Overview

The drugs of cardiac arrest, shock and symptomatic bradycardia — adrenaline, the vasopressors/inotropes, atropine, and glucagon for β-blocker/CCB overdose.

Mechanism

Adrenaline: α₁ (vasoconstriction) + β₁ (inotropy/chronotropy) + β₂ (bronchodilation). Noradrenaline: mainly α₁ → vasoconstriction (septic shock). Dobutamine: β₁ → inotropy (cardiogenic shock). Atropine: antimuscarinic → blocks vagal tone → ↑heart rate. Glucagon raises cardiac cAMP independent of β-receptors → reverses β-blocker overdose.

Indications

  • Cardiac arrest (adrenaline)
  • Anaphylaxis (adrenaline IM — cross-ref)
  • Shock — septic (noradrenaline) / cardiogenic (dobutamine)
  • Symptomatic bradycardia (atropine)
  • β-blocker / CCB overdose (glucagon, calcium)

The agents

Adrenalinearrest / anaphylaxis

1 mg IV (arrest); 0.5 mg IM 1:1000 (anaphylaxis)

Non-shockable: ASAP; shockable: after 3rd shock, then every 3–5 min.

Noradrenalinevasopressor (α₁)

central IV infusion

Septic/distributive shock — first-line vasopressor.

Dobutamineinotrope (β₁)

IV infusion

Cardiogenic shock / low output.

Atropineantimuscarinic

500 mcg IV, repeat to max 3 mg

Symptomatic bradycardia; then transcutaneous pacing/isoprenaline/adrenaline.

Glucagonβ-blocker/CCB OD

IV

Bypasses the β-receptor; calcium for CCB overdose.

Adverse effects

Arrhythmias, hypertension, tissue ischaemiaserious

Vasopressors — central line (extravasation necrosis).

Atropine: dry mouth, urinary retention, confusioncommon
Adrenaline: anxiety, tremor, palpitationscommon

Cautions & contraindications

Peripheral infusion of noradrenaline (extravasation)all

Tissue necrosis — give centrally.

IV adrenaline 1:1000 in anaphylaxisall

Anaphylaxis dose is IM 1:1000; IV 1:10,000 is for arrest only.

Interactions

  • Beta-blockers blunt adrenaline (→ glucagon in refractory anaphylaxis)
  • MAOIs potentiate sympathomimetics

Monitoring & kinetics

Continuous ECG/BP; arterial line for vasopressors; cardiac monitoring

IV/infusion (central for vasopressors); adrenaline IM for anaphylaxis.

Source: Resus Council UK — ALS / bradycardia · BNF — Sympathomimetics