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Anticholinergic / Parasympatholytic Pregnancy: Use with caution — crosses placenta; causes fetal tachycardia. Used in obstetric RSI.

Atropine (Anaesthesia/Bradycardia)

Brand names: Minims Atropine, Atropin

Adult dose

Dose: Bradycardia: 0.5–1 mg IV; Pre-medication: 300–600 mcg IM; NMB reversal adjunct: 600 mcg–1.2 mg IV with neostigmine
Route: IV / IM
Frequency: Single dose; repeat as needed for bradycardia
Max: 3 mg total (full vagal blockade)
ALS algorithm: 0.5 mg IV for symptomatic bradycardia (HR <60 with adverse features); repeat up to 3 mg. Doses <0.3 mg can paradoxically cause bradycardia (central vagal stimulation) — always use ≥0.5 mg IV.

Paediatric dose

Dose: 0.02 mg/kg
Route: IV / IM
Frequency: Single dose; repeat as needed
Max: 0.6 mg
Min dose 0.1 mg (paradoxical bradycardia at lower doses). Pre-medication before suxamethonium or intubation in children: 0.02 mg/kg IV.

Dose adjustments

Renal

No dose adjustment required.

Hepatic

No dose adjustment required.

Paediatric weight-based calculator

Min dose 0.1 mg (paradoxical bradycardia at lower doses). Pre-medication before suxamethonium or intubation in children: 0.02 mg/kg IV.

Clinical pearls

  • Critical minimum dose: never give <0.5 mg IV — paradoxical bradycardia occurs at low doses due to central vagal stimulation
  • In NMB reversal: give atropine BEFORE or simultaneously with neostigmine to prevent bradycardia from neostigmine's muscarinic effects; glycopyrrolate now preferred as longer-acting
  • ALS 2021: atropine no longer in asystole/PEA algorithm — only used for symptomatic sinus bradycardia

Contraindications

  • Tachyarrhythmias
  • Acute angle-closure glaucoma
  • Paralytic ileus
  • Myasthenia gravis (relative)

Side effects

  • Tachycardia
  • Dry mouth
  • Urinary retention
  • Blurred vision (mydriasis)
  • CNS excitation (high doses — especially elderly)
  • Paradoxical bradycardia (doses <0.3 mg IV)

Interactions

  • Antihistamines/TCAs (additive anticholinergic effects)
  • Neostigmine (atropine given first to block muscarinic effects before neostigmine)

Monitoring

  • HR and ECG
  • Blood pressure

Reference: BNFc; BNF 90; Resuscitation Council UK ALS Guidelines 2021; BNFc. Verify against your local formulary and the latest BNF before prescribing.

Related

Curated clinical cross-links plus same-class fallbacks.

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