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# Atropine
## Overview
Atropine is an anticholinergic medication that competitively inhibits the action of acetylcholine at muscarinic receptors. It can cause increased heart rate, decreased secretions, bronchodilation, and mydriasis.
## Primary Indications
* Bradycardia (symptomatic)
* Organophosphate poisoning
* Antidote for anticholinesterase agents
* Preoperative medication to reduce secretions
## Adult Dosing
* **Symptomatic Bradycardia:** 0.5 mg IV every 3-5 minutes as needed. Maximum dose is generally not well-defined but guided by clinical response. Doses below 0.5 mg may be less effective and can cause paradoxical bradycardia.
* **Organophosphate Poisoning:** Large doses are often required. Initial dose: 1-2 mg IV, then titrate to effect (e.g., drying of secretions, improved heart rate, decreased bronchospasm). Doses of 2-5 mg IV or IM every 5-60 minutes may be needed. Continuous infusion may be necessary in severe cases.
* **Preoperative:** 0.4-0.6 mg IM or IV 30-60 minutes before surgery.
## Pediatric Dosing
* **Symptomatic Bradycardia:** 0.02 mg/kg IV or IM per dose, with a minimum dose of 0.1 mg and a maximum dose of 0.5 mg per dose. May be repeated every 3-5 minutes.
* **Organophosphate Poisoning:** 0.05 mg/kg IV, may be repeated every 10-20 minutes until muscarinic symptoms are controlled. Subsequent doses may be given every 1-10 hours depending on clinical response.
## Dose Adjustments
* No specific dose adjustments are typically required for hepatic or renal impairment, but caution is advised.
## Contraindications
* Tachycardia
* Glaucoma (narrow-angle)
* Myasthenia gravis
* Hypersensitivity to anticholinergics
## Adverse Effects
Common: Dry mouth, blurred vision, photophobia, urinary retention, constipation, tachycardia, drowsiness, confusion.
Severe: Severe tachycardia, arrhythmias, central nervous system excitation (delirium, hallucinations), heatstroke (due to decreased sweating).
## Key Drug Interactions
* **Anticholinergics:** Additive anticholinergic effects.
* **Beta-blockers:** May potentiate atropine-induced tachycardia.
* **Proton Pump Inhibitors (PPIs):** May reduce the efficacy of PPIs due to increased gastric pH.
* **Other Drugs:** Effects may be altered by other medications affecting the autonomic nervous system.
## Monitoring
* Heart rate and rhythm
* Blood pressure
* Pupil size
* Mental status
* Urine output
* Gastrointestinal motility (for constipation)
* Pulmonary status (secretions, wheezing)
## Clinical Pearls
* In symptomatic bradycardia, atropine is generally preferred over other agents if there is no contraindication.
* For organophosphate poisoning, large and frequent doses may be required; monitor closely for signs of adequate effect and anticholinergic toxicity.
* IV administration is preferred for rapid onset. IM route is an alternative.
* Atropine may cause paradoxical bradycardia if doses below 0.5 mg are used in adults.
**Disclaimer:** This information is intended for healthcare professionals and is not a substitute for professional medical advice. Always consult the most current prescribing information and relevant clinical guidelines before making any treatment decisions.
