Anticholinergic / Parasympatholytic

Atropine (Anaesthesia/Bradycardia)

Brand names: Minims Atropine, Atropin

Atropine is an antimuscarinic (anticholinergic) agent used for symptomatic bradycardia, as an antisialagogue to reduce secretions, and as an antidote in organophosphate, carbamate and nerve-agent (cholinergic) poisoning.

Dosing — being independently re-sourced

ClinCalc Pro is rebuilding its dose data from primary open sources — the manufacturer SmPC (eMC), the WHO Model Formulary and other official references — under clinician review. This drug's structured dose is not yet published here. Confirm all doses against the product SmPC and your local formulary before prescribing.

US labelling (FDA)

Reference — US labelling, may differ from UK

2 DOSAGE & ADMINISTRATION 2.1 General Administration Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit. Do not administer unless solution is clear and seal is intact. Each vial is intended for single dose only. Discard unused portion. For Intravenous administration. Titrate based on heart rate, PR interval, blood pressure and symptoms. 2.2 Adult Dosage 2.3 Pediatric Dosage Dosing in pediatric populations has not been well studied. Usual initial dose is 0.01 to 0.03 mg/kg. 2.4 Dosing in Patients with Coronary Artery Disease Limit the total dose of atropine sulfate to 0.03 to 0.04 …

Source: US FDA prescribing information (openFDA / DailyMed), label dated 2024-01-28. Accessed 2026-06-12. US dosing and indications can differ from UK practice — use UK sources for prescribing decisions.

Clinical monograph

How it works

It competitively blocks muscarinic acetylcholine receptors, reducing vagal tone on the heart (increasing rate and AV conduction), drying secretions, and reversing the muscarinic effects of cholinergic excess.

Prescribing in practice

In organophosphate or nerve-agent poisoning, large repeated doses are titrated against secretions and chest signs (the aim is a dry chest), not against heart rate — far more may be needed than for bradycardia.
Predictable antimuscarinic effects include tachycardia, dry mouth, urinary retention, blurred vision with pupil dilatation, flushing and reduced sweating.
Central antimuscarinic toxicity (confusion, agitation, delirium) is common in older people; use cautiously where tachycardia is hazardous, such as acute coronary ischaemia.

Monitoring

Monitor heart rate, rhythm and blood pressure continuously when treating bradycardia; in poisoning, track respiratory secretions, chest auscultation and oxygenation as the endpoint of titration, and watch for urinary retention and confusion.

Counselling the patient

Warn the team and recovery staff to expect a dry mouth, blurred vision, dilated pupils and a faster heart rate.
In conscious patients or carers, advise reporting difficulty passing urine, marked agitation or confusion.
For poisoning, follow Toxbase/NPIS advice and titrate to drying of secretions rather than to a target pulse.

Evidence & guidelines

Recommended for symptomatic bradycardia (Resuscitation Council UK) and as a cholinergic-poisoning antidote (Toxbase/NPIS).

Reference: Resuscitation Council UK ALS Guidelines 2021; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways