Atropine: Clinical Guidelines for Use in Adults and Children
Atropine is the first-line treatment for symptomatic bradycardia in adults at 0.5-1 mg IV, repeated every 3-5 minutes up to 3 mg total, but should NOT be used routinely for pediatric emergency intubation premedication. 1, 2
Adult Indications and Dosing
Primary Indications
Atropine is indicated for the following life-threatening conditions 3, 2:
- Symptomatic sinus bradycardia (heart rate <50 bpm with hypotension, ischemia, or escape ventricular arrhythmias) 3, 2
- Ventricular asystole 3, 2
- Symptomatic AV block at the AV nodal level (second-degree type I or third-degree with narrow-complex escape rhythm) 3, 2
- Organophosphate or muscarinic mushroom poisoning (initial dose 2-3 mg, repeated every 20-30 minutes) 4
Standard Adult Dosing Algorithm
Follow this stepwise approach 1, 2, 4:
- Initial dose: 0.5-1 mg IV (never give <0.5 mg due to paradoxical bradycardia risk) 1, 2, 4
- Repeat every 3-5 minutes as needed 1, 2
- Maximum total dose: 3 mg 1, 2, 4
- If no response after maximum atropine, initiate transcutaneous pacing or IV infusion of dopamine (5-10 mcg/kg/min) or epinephrine (2-10 mcg/min) 1
Critical Dosing Warnings
Never administer doses <0.5 mg, as this can cause paradoxical bradycardia through a vagotonic effect at the sinoatrial node 1, 2, 5. This is particularly dangerous in patients already hemodynamically compromised 6.
In patients with coronary artery disease, limit total dose to 0.03-0.04 mg/kg to avoid worsening ischemia or increasing infarct size 3, 4.
Pediatric Use
Emergency Intubation Premedication
The 2015 American Heart Association guidelines explicitly state that routine atropine premedication for pediatric emergency intubation is NOT supported by evidence. 3
However, atropine may be reasonable in specific high-risk scenarios 3:
- When using succinylcholine as the neuromuscular blocker 3
- Pediatric dose: 0.02 mg/kg IV with no minimum dose (this represents a change from older guidelines that recommended a 0.1 mg minimum) 3
The evidence shows no improvement in survival or cardiac arrest prevention with routine preintubation atropine in children, though observational data suggest possible benefit in children >28 days old 3.
Pediatric Bradycardia Dosing
For symptomatic bradycardia in children, the usual initial dose is 0.01-0.03 mg/kg 4.
When Atropine Will NOT Work
Contraindicated or Ineffective Scenarios
Atropine is unlikely to be effective and should not delay other interventions in 3, 1, 2:
- Type II second-degree AV block 3, 1, 2
- Third-degree AV block with wide-QRS complex (infranodal block) 3, 1, 2
- Atrioventricular block at the infranodal level (usually associated with anterior MI) 3
- Heart transplant patients without autonomic reinnervation (may cause paradoxical high-degree AV block) 1, 6, 2
In these situations, proceed directly to transcutaneous pacing or catecholamine infusions 1.
Special Clinical Situations
Acute Myocardial Infarction
Use atropine with extreme caution in acute MI, as increasing heart rate may worsen ischemia or extend infarct size 3, 1, 2. Atropine is most effective when used within 6 hours of symptom onset, particularly for bradycardia related to ischemia, reperfusion (Bezold-Jarisch reflex), or medication effects (morphine, nitroglycerin) 3.
Titrate to achieve a minimally effective heart rate of approximately 60 bpm, not higher 3.
Inferior vs. Anterior MI
- Inferior MI with AV block: Atropine improved AV conduction in 85% of patients in one study 7
- Anterior MI with wide-complex escape: Atropine is contraindicated; use pacing instead 3
Drug Interactions
In patients taking clozapine (which has significant anticholinergic properties), atropine use requires intensive monitoring for 6:
- Central anticholinergic syndrome (confusion, hallucinations, fever) 6
- Dangerous tachyarrhythmias 6
- Severe constipation 6
Consider alternatives such as transcutaneous pacing, dopamine, or epinephrine infusions when possible 6.
Common Pitfalls and How to Avoid Them
Pitfall #1: Delaying Pacing in Unstable Patients
Do not delay transcutaneous pacing while giving multiple atropine doses in hemodynamically unstable patients 1. If the first dose of atropine fails and the patient has severe hypotension (systolic BP <80 mmHg) or signs of shock, apply pacing immediately 1.
Pitfall #2: Excessive Dosing
Exceeding 3 mg total dose or giving doses >1 mg initially increases risk of 3, 7:
- Ventricular tachycardia or fibrillation 7
- Sustained sinus tachycardia 7
- Central anticholinergic syndrome (confusion, agitation, hallucinations) 1
- Toxic psychosis 7
Pitfall #3: Using Atropine for Asymptomatic Bradycardia
Asymptomatic sinus bradycardia is a Class III indication (not recommended) for atropine 3. Only treat bradycardia when accompanied by hypotension, altered mental status, chest pain, acute heart failure, or shock 1, 2.
Alternative Treatments When Atropine Fails
Second-Line Agents
If atropine is ineffective or contraindicated, use 1:
- Transcutaneous pacing (Class IIa recommendation for unstable patients) 1
- Dopamine infusion: 5-10 mcg/kg/min IV, titrated to effect 1
- Epinephrine infusion: 2-10 mcg/min IV, titrated to effect 1
Choosing Between Dopamine and Epinephrine
Dopamine is preferred when inotropic support is needed, as it provides more titratable, dose-dependent effects with less vasoconstriction at lower doses 1. Epinephrine has stronger alpha-adrenergic effects causing more profound vasoconstriction 1.
Isoproterenol (20-60 mcg IV bolus or 1-20 mcg/min infusion) may be preferable in ischemic cardiomyopathy, as it provides chronotropic and inotropic effects without vasopressor effects 1.
Monitoring Requirements
During and after atropine administration, continuously monitor 1: