Atropine

Tertiary ammonium alkaloid ester of tropic acid
Naturally occurs in plant sources
1. Atropa belladonna (Deadly nightshade)
2. Datura stramonium (Jimsonweed, Thorn apple)
Described as Belladonna (beautiful woman) alkaloid
1. Women of past used Atropine to dilate pupils
2. Mydriasis was perceived as more attractive
Related isomer to Scopolamine (Hyoscine)

Antimuscarinic Cholinoceptor blocking drug
Causes parasympathetic blockade (parasympatholytic)
Inhibits vagal nerve activity (vagolytic)
1. Enhances Sinus node automaticity
2. Enhances Atrioventricular Node (AV) conduction

Symptomatic Bradycardia associated with
1. Poor perfusion
2. Hypotension
Relative Bradycardia
Prevent vagally mediated Bradycardia with intubation
Symptomatic Bradycardia with AV Block
Asystole or Pulseless Electrical Activity
1. No evidence that survival is improved with Atropine
2. Asystole is nearly always fatal despite intervention
Nerve Agent Exposure

IV Dose
1. Dose: 0.02 mg/kg IV or IO every 5 minutes for up to 2 to 3 doses
2. Minimum Dose: 0.1 mg
3. Maximum Dose
  1. Child: 0.5 mg
  2. Teen: 1.0 mg
Endotracheal Dose (IV/IO is preferred)
1. Dose: 2-3x IV dose (0.06 mg/kg) diluted in 3-5cc NS
2. Follow dose with several positive pressure breaths

Bradycardia
1. Dose: 0.5-1.0 mg IV
2. May repeat every 3-5 min to max total dose of 0.04 mg/kg or 3 mg
Asystole or Bradycardic Pulseless Electrical Activity
1. Dose: 1 mg IV
2. Consider giving entire 0.04 mg/kg at start)
3. May repeat q3-5 min to max total dose of 0.04 mg/kg
Endotracheal Dosing (IV/IO is preferred)
1. Dose: 1-2 mg per dose
2. Dilute to 10 ml with sterile water or saline

See Nerve Agent Exposure
Adjunct to Pralidoxime chloride (2-PAMCl)
Atropine (Preservative-free) is indicated for muscarinic effects (bronchorrhea, bronchospasm, Bradycardia)
Goal: Drying of secretions (will not reverse neuromuscular effects, Muscle Weakness or Respiratory Failure)
1. Repeat doses until Shortness of Breath and Wheezing resolve and excess secretions reduce
Adult
1. Dose 1-2 mg slow IV push (up to 2-5 mg IV) every 15 minutes as needed
2. May be given as often as every 3-5 minutes, doubling dose
3. Most effective for pulmonary symptoms in adults
4. Very high doses (e.g. 40 mg) may be needed
5. Autoinjectors contain 2 mg Atropine
Child <12 years
1. Dose 0.015 to 0.05 mg/kg slow IV push (up to 0.1 mg/kg) every 15 minutes as needed
2. May be given as often as every 3-5 minutes, doubling dose
3. Most effective for CNS symptoms in children
4. Pediatric autoinjectors are available
  1. Use 0.25 mg pen for weight <7 kg, 0.5 mg pen if 7 to 18 kg and 1 mg if 18 to 41 kg
  2. Use adult dose or adult autoinjector (2 mg) if weight >41 kg
Taper dose, and discontinue by 24 hours
Atropine may be continued as drip at 0.5 to 2.4 mg/kg/h
1. Indicated for persistent symptoms (up to 48 hours may be needed in severe cases)

Avoid repeat dosing if possible
1. Increases myocardial oxygen demand
2. Atropine may provoke Ischemic Heart Disease
Consider external pacing if repeat dosing needed
Avoid dosing Atropine below recommended dose
1. Causes paradoxical Bradycardia
2. May precipitate Ventricular Fibrillation

Rebound Tachycardia
Paradoxical Bradycardia (if low dose Atropine used)
Pupil dilatation (Mydriasis)
Paradoxical rate slowing
1. Type II Second degree AV Block
2. Third Degree AV Block
Arrhythmia (especially in Coronary Artery Disease)
1. Ventricular Fibrillation
2. Ventricular Tachycardia
Anticholinergic Toxicity with overdosage
Decreased Sweating and secretions
Mild sedation to Delirium