Anticholinergic
Pregnancy: C
Atropine
Brand names: Atropine Sulphate
Adult dose
Dose: 0.5–1mg
Route: IV
Frequency: Repeat every 3–5 min as needed
Max: 3mg (total vagal block)
Symptomatic bradycardia: 0.5mg IV, repeat to 3mg total. Organophosphate poisoning: titrate until secretions dry (may need >10mg). Pre-medication: 600mcg IM/IV.
Paediatric dose
Dose: 0.02 mg/kg
Route: IV
Frequency: Single dose, repeat if needed
Max: 0.6mg
Concentration: 0.6 mg/ml
Paediatric weight-based calculator
Clinical pearls
- Minimum adult dose 0.5mg to avoid paradoxical bradycardia (vagal stimulation). Minimum paed dose 0.1mg.
- Not first-line for high-degree AV block with broad QRS escape — use adrenaline infusion 2–10 mcg/min or transcutaneous pacing.
- Organophosphate poisoning: give until secretions dry, pupils dilate. May need 10–20mg total — no fixed maximum.
- Reversed by physostigmine (rarely required).
Contraindications
- Acute angle-closure glaucoma
- Obstructive uropathy
- Myasthenia gravis (except for neostigmine reversal)
Side effects
- Tachycardia, dry mouth, urinary retention
- Blurred vision, mydriasis
- Confusion and agitation (especially elderly)
- Paradoxical bradycardia at doses below 0.5mg (adults)
Interactions
- Other anticholinergics: additive effects — urinary retention, confusion
- Cisapride, metoclopramide: reduced prokinetic effect
Reference: BNFc; NICE BNF 84; UK ALS Guidelines 2021. Verify against your local formulary and the latest BNF before prescribing.
Related
Curated clinical cross-links plus same-class fallbacks.