Lippincott Nursing Pocket Card - April 2023

Atropine Sulfate


Atropine Sulfate

Atropine is an anticholinergic drug. Atropine blocks the action of acetylcholine at parasympathetic sites in smooth muscle, secretory glands, and the central nervous system, which leads to increased cardiac output and dries secretions. It is a competitive, reversible antagonist of muscarinic receptors and can be used to reverse the muscarinic effects of cholinergic poisoning (Lexicomp, n.d.). Atropine may be administered subcutaneously, intramuscularly (IM), intravenously (IV), intraosseous, or by endotracheal tube (ET). Intravenous is the preferred method. For ET administration, dilute 1 mg to 2 mg in 10 mL of sterile water or normal saline (McLendon & Preuss, 2021).

Atropine Sulfate
(Facts and Comparisons, 2022)
Approved Indications Dosage
Bradycardia during neuromuscular blockade reversal
  • 5 to 7 mcg/kg IV when administered with edrophonium
  • 15 to 20 mcg/kg IV when administered with neostigmine
  • Maximum total dosage: 3 mg
Sinus bradycardia, symptomatic
  • 0.5 to 1 mg IV or IM every 3 to 5 minutes
  • 1 mg is preferred for severe bradyarrhythmias (i.e., hypotension/shock, altered mental status, acute heart failure)
  • Endotracheal: 1 to 2 mg every 3 to 5 minutes
  • Maximum total dosage: 3 mg
Preoperative/preanesthetic medication to inhibit salivation and secretion
  • 0.5 to 1 mg IM, IV or subcutaneously 30 to 60 minutes preoperatively; repeat very 4 to 6 hours as needed
  • Maximum total dosage: 3 mg
Treatment of symptoms from muscarine-containing mushroom poisoning
  • 1 to 2 mg IV; titrate and repeat as needed to reverse symptoms (i.e., titrate to decreased bronchial secretions)
Antidote for anticholinesterase poisoning (carbamate insecticides, nerve agents, organophosphate insecticides)
  • Mild to Moderate symptoms: 1 to 2 mg IV bolus; repeat by doubling the dose every 3 to 5 minutes if previous dose did not induce a response; repeat doses as needed for 2 to 12 hours for recurrence of symptoms; consider starting IV continuous infusion for improved clinical outcomes.
  • Severe symptoms: 3 to 5 mg IV bolus and repeat as above; consider IV continuous infusion.

Note: The safety and efficacy of atropine in pediatric patients has not been fully studied. Consult the complete product insert for pediatric dosing.


Administration and Monitoring (Lexicomp, n.d.)

IV doses less than 0.5 have been associated with paradoxical bradycardia. For patients with ischemic heart disease, the dose should be limited to 0.03 – 0.04 mg/kg. The typical initial pediatric dose is 0.01 to 0.03 mg/kg, (although pediatric dosing has not been well researched). Monitor heart rate, PR interval, blood pressure, and mental status closely. IV administration requires a cardiac monitor.

Side Effects

Common side effects of atropine include dry mouth, blurred vision, photophobia, tachycardia, flushed skin, constipation, difficulty with urination, inability to perspire appropriately, delirium or coma (McLendon & Preuss, 2021).

Precautions (Pfizer, 2020)

Atropine may cause adverse effects in patients with the following conditions:
  • Known hypersensitivity
  • Tachycardia
  • Suspected glaucoma: atropine may precipitate acute glaucoma
  • Pyloric stenosis: atropine may cause complete obstruction
  • Prostatic hypertrophy: atropine may cause urinary retention in these patients
Atropine should be used with caution in patients with fever and in patients with thyrotoxicosis, cardiac insufficiency, and in cardiac surgery where it may further increase the heart rate.

Drug-Drug Interactions (Pfizer, 2020)

The action of atropine may be enhanced by tricyclic antidepressants, monoamine oxidase inhibitors (MAOI’s), phenothiazine, amantadine, some antihistamines, butyrophenones, and disopyramide.

Overdose (Pfizer, 2020)

The following symptoms could signal overdose: palpitations, dilated pupils, difficulty swallowing, hot dry skin, thirst, dizziness, restlessness, tremor, fatigue, and ataxia. Toxic doses can cause palpitations, restlessness, hallucinations, delirium, and coma. Severe overdose may result in circulatory collapse, respiratory failure, paralysis, and coma. Treatment of toxic overdose include a short-acting barbiturate or diazepam to treat excitement and convulsions. Physostigmine (1 to 4 mg) is an atropine antidote administered  by slow IV injection. Repeat doses may be required.

Facts and Comparisons (2022, April 4). Atropine Injection.
Lexicomp. (n.d.). Atropine (systemic): Drug information. UpToDate. Retrieved March 27, 2023, from  
McLendon, K. & Preuss, C.V. (2021, September 12). Atropine. StatPearls.
Pfizer. (2020, Jully). Atropine Sulfate Injection USP.