Main emergency uses

1. Symptomatic bradycardia
   • For a slow heart rate causing hypotension, altered mental status, shock, ischemic chest discomfort, or acute heart failure.
   • Usual adult ACLS dose: 1 mg IV/IO, repeat every 3 to 5 minutes, maximum 3 mg.
   • It works best in vagal or sinus-node mediated bradycardia. If ineffective, pacing or epinephrine/dopamine infusion may be needed.
   • It is not recommended for asystole or pulseless electrical activity. Tintinalli's Emergency Medicine, 9e.
2. Organophosphate pesticide or nerve-agent poisoning
   • Used for the muscarinic toxicity: profuse airway/oral secretions, bronchospasm, wheeze, severe bradycardia, sweating, lacrimation, diarrhea, and miosis.
   • The immediate clinical target is improvement in breathing and drying of bronchial secretions, not simply a normal heart rate or pupil size.
   • Large repeated doses may be required, with airway support, decontamination, and often pralidoxime as part of specialist toxicology care. The CDC organophosphate guidance identifies atropine as treatment for excessive bronchial secretions, a frequent life-threatening feature.
3. Vagal bradycardia during emergency procedures
   • May be used for marked bradycardia related to airway manipulation, suctioning, certain anesthetic/procedural events, or other vagal stimulation.
   • In selected children at high risk of vagal bradycardia during emergency intubation, clinicians may use it as premedication.

Important cautions

• Give oxygen, monitor ECG, blood pressure, and clinical response.
• It can cause tachycardia, myocardial ischemia, urinary retention, dry mouth, hyperthermia, agitation, and delirium.
• It may be ineffective in high-grade infranodal AV block or transplanted-heart bradycardia, where pacing is often more appropriate.
• In suspected poisoning with breathing difficulty, copious secretions, seizures, collapse, or confusion, call emergency services immediately. Do not attempt to self-administer atropine.

Key emergency uses

1. Anaphylaxis
   • First-line treatment for airway swelling, wheeze, breathing difficulty, low blood pressure, collapse, or widespread allergic reaction.
   • Adult: 0.5 mg intramuscularly into the outer thigh, using 1 mg/mL (1:1000) solution. Repeat after about 5 minutes if symptoms persist.
   • An auto-injector should be used immediately if available, followed by emergency services.
   • There are no absolute contraindications when anaphylaxis is suspected. Antihistamines do not replace adrenaline. ROSEN's Emergency Medicine, 10e.
2. Cardiac arrest
   • Given by trained resuscitation teams during CPR.
   • Adult ACLS: 1 mg IV or intraosseous every 3 to 5 minutes.
   • It supports coronary and brain perfusion during CPR. For shockable rhythms, defibrillation and high-quality CPR remain the priority. The AHA adult life-support guideline recommends 1 mg every 3 to 5 minutes.
3. Severe asthma or upper-airway obstruction
   • May be used in selected severe, life-threatening cases, especially where anaphylaxis is suspected or there is marked airway swelling. This requires urgent medical assessment.
4. Refractory anaphylactic shock
   • If repeated IM doses, oxygen, and IV fluids fail, clinicians may start a carefully titrated IV adrenaline infusion with continuous monitoring. IV bolus adrenaline is risky and should not be used routinely for anaphylaxis. Tintinalli's Emergency Medicine, 9e.

Important distinction from atropine