Atropine
Atropine sulfate
Brand names:AtroPen, DuoDote (combined with pralidoxime)
A competitive antagonist at muscarinic acetylcholine receptors used to reverse the muscarinic effects of organophosphate and nerve agent poisoning, treat symptomatic bradycardia, and reduce secretions during airway procedures. Atropine is the primary antidote for nerve agent exposure and the first drug administered in confirmed organophosphate toxicity.
Pharmacology and Actions
Competitively blocks acetylcholine at muscarinic receptors throughout the body, reversing the muscarinic effects of cholinergic excess: pupillary constriction, lacrimation, salivation, bronchorrhea, bronchospasm, vomiting, diarrhea, urination, bradycardia, and hypotension. Does not affect nicotinic receptors, so does not reverse skeletal muscle paralysis or fasciculations from nerve agent or organophosphate exposure. Has central nervous system effects at higher doses.
Indications
- Nerve agent or organophosphate poisoning (primary indication in tactical and CBRN settings)
- Symptomatic bradycardia with hemodynamic compromise
- Reduction of secretions during emergency airway procedures
- Antidote for muscarinic mushroom poisoning (Amanita muscaria, Inocybe)
Absolute Contraindications
- None in the setting of life-threatening nerve agent or organophosphate exposure
- In other settings: narrow-angle glaucoma
- Mechanical bowel obstruction
- Severe ulcerative colitis with toxic megacolon
- Obstructive uropathy
- Myasthenia gravis without supportive care
Precautions and Side Effects
Tachycardia, dry mouth, mydriasis, urinary retention, anhidrosis with hyperthermia (heat stroke risk in operational environments), CNS effects at high doses (confusion, hallucinations, hyperthermia, seizures). Anticholinergic toxidrome at therapeutic doses for nerve agent. Re-dose to effect: drying of secretions and resolution of bronchospasm are the endpoints, NOT pupillary dilation or heart rate.
Adult Dosing
Pediatric Dosing
Nerve agent or organophosphate: 0.05 mg/kg IV/IO, minimum 0.1 mg, maximum 2 mg per dose, repeat every 5 to 15 minutes. AtroPen auto-injector pediatric sizes available (0.5 mg, 1 mg). Bradycardia: 0.02 mg/kg IV/IO, minimum 0.1 mg, max 0.5 mg per dose.
Pharmacokinetics
Peak Effect: IV 2 to 4 minutes; IM 30 minutes
Duration: 4 to 6 hours (longer in CNS effects)
Storage and Handling
Room temperature 20 to 25 degrees C; protect from light. AtroPen auto-injectors stored at room temperature; check expiration dates as some military stocks have extended expiration through shelf life extension programs. Single-use auto-injector design with spring-loaded needle.
Reconstitution:
Pre-filled syringes and auto-injectors do not require reconstitution. Multi-dose vials available in 0.4 mg/mL and 1 mg/mL concentrations.
TCCC and TECC Role
Primary antidote for nerve agent and organophosphate exposure in CBRN response. Not a TCCC core formulary medication for conventional trauma but essential for tactical CBRN events. AtroPen and DuoDote auto-injectors are standard in DOD CBRN response kits and many civilian hazmat and tactical EMS kits.
Atropine for nerve agent is a use-aggressively, dose-to-effect drug. The doses required to reverse severe organophosphate or nerve agent toxicity are orders of magnitude higher than typical clinical use. A casualty with sarin exposure may need 20 to 50 mg or more of atropine over the first hour. The endpoint is not the heart rate or pupil size but the resolution of secretions and bronchospasm. Atropine alone does not address the nicotinic effects (muscle paralysis, fasciculations); pralidoxime is required to reactivate the affected acetylcholinesterase enzyme. The two are paired in the DuoDote auto-injector and the Mark I antidote kit for this reason.
Under-dosing in severe nerve agent exposure. The clinical doses for bradycardia (0.5 to 1 mg) are not adequate for nerve agent reversal. Start at 2 to 6 mg and titrate aggressively. The other common mistake is using heart rate or pupil dilation as the endpoint; the correct endpoints are drying of secretions and resolution of bronchospasm. Operationally, anhidrosis from atropine creates heat stroke risk in hot environments; monitor temperature aggressively in a casualty receiving repeated atropine doses.
This drug profile is provided as educational reference material for trained medical providers. It is not medical advice, not a substitute for formal training, and not a substitute for current published guidelines or medical direction.
Drug administration is governed by your scope of practice, agency standing orders, medical director protocols, and applicable state and federal regulations. Controlled substances are subject to additional handling, accountability, and documentation requirements per DEA and state law. Always verify dosing, indications, contraindications, and route of administration against current published guidelines and your local protocols before administration.
If this content is being viewed during a medical emergency, call 911 immediately and follow the direction of your local emergency dispatch and medical control. Do not use this reference as a substitute for emergency medical services.
Drug information evolves. Last reviewed dates and source citations are provided for each entry. Confirm currency against the cited source before clinical use.
Penn Tactical Solutions publishes this reference for educational purposes. PTS does not provide medical direction and does not assume responsibility for clinical decisions made in the field. Clinical responsibility rests with the administering provider, their medical director, and their agency.
Educational reference for trained medical providers. Not medical advice. Not a substitute for formal training, current published guidelines, or medical direction. Drug administration is governed by your scope of practice, agency standing orders, medical director protocols, and applicable state and federal regulations. Controlled substances require additional storage, accountability, and documentation per DEA and state law.
In a medical emergency, call 911. This reference is not a substitute for emergency medical services.
Verify dosing, indications, and contraindications against current published guidelines and your local protocols before administration. Confirm content currency against the source citation. Penn Tactical Solutions does not provide medical direction. Clinical responsibility rests with the administering provider, their medical director, and their agency.
Atropine
| IV/IO | Nerve agent or organophosphate poisoning: 2 to 6 mg IV initial dose, repeat every 5 to 15 minutes until drying of secretions and resolution of bronchospasm. No maximum dose in severe poisoning. Bradycardia: 0.5 to 1 mg IV every 3 to 5 minutes, max 3 mg. (1 minute) |
| IM | Nerve agent or organophosphate poisoning: 2 mg IM via AtroPen or DuoDote (combined with 600 mg pralidoxime). Mild exposure: 1 AtroPen. Moderate: 2 AtroPens. Severe: 3 AtroPens given in rapid succession. Re-dose every 5 to 15 minutes based on symptom resolution. (5 to 15 minutes) |
| IN | None (None) |
| PO | None (None) |