Disclaimer to the On-line Edition
This Manual has been designed for use in the NICU at London Health Sciences Centre (LHSC), London, Ontario, Canada, and represents clinical practice at this institution. The information contained within the Manual may not be applicable to other centres. If users of this Manual are not familiar with a drug, it is recommended that the official monograph be consulted before it is prescribed and administered. Any user of this information is advised that the contributors, Editor and LHSC are not responsible for any errors or omissions, and / or any consequences arising from the use of the information in this Manual.



  • the treatment of sinus bradycardia, particularly when related to parasympathetic influences (digoxin, beta blocking agents, hyperactive carotid sinus reflex). Persistent bradycardia usually represents persistent hypoxia
  • also used during cardiopulmonary resuscitation


  • atropine is a naturally occurring antimuscarinic drug
  • antimuscarinic drugs competitively inhibit the action of acetylcholine on muscarinic receptors (including smooth and cardiac muscle, exocrine glands and postganglionic cholinergic nerve terminals)
  • atropine can initially cause bradycardia, an effect which is usually transient and mild; the heart rate then returns to normal, or increases, depending on the dose and the vagal input into the heart rate at the time
  • the time to peak tachycardia is 12 to 16 minutes; the duration of action is 6h
  • can cause cardiac arrhythmias, especially during the first 2 minutes after IV administration; this tends to occur more with low, rather than large, doses

Side Effects

  • low doses: dilated pupils, dry mucous membranes, flushed skin with rash, fever, hyperthermia
  • higher doses: tachycardia, abdominal distention with absent bowel activity, urinary retention, sedation followed by excitation, cardiac arrhythmias


  • atropine is INCOMPATIBLE with many other drugs (eg. sodium bicarbonate); therefore, DO NOT mix atropine with other drugs
  • myocardial oxygen consumption and ischemia may be increased by atropine-induced tachycardia and may aggravate heart failure
  • rapid IV administration of atropine may cause ventricular tachycardia and fibrillation


  • For prolonged cardiopulmonary resuscitation and bradycardia:
    • 0.01 to 0.03 mg/kg (10 to 30 mcg/kg) by IV push, over 1 minute, given by a physician; may repeat every 2-10 minutes, suggested maximum total dose of 0.04 mg/kg (40 mcg/kg)
    • may also administer via endotracheal tube, suggested dose is 2 to 3 times IV dose

  • For Elective Intubation:
    • 0.02 mg/kg (20 mcg/kg) by IV push, over 1 minute, given by an MD/CNS


  • the 0.4 mg/mL (400 mcg/mL) ampoule can be diluted to 25 mcg/mL to facilitate administration of the drug
    1. Inject 1 mL of 400 mcg/mL into a 20 mL syringe
    2. Add 15 mL sterile water for injection to the 20 mL syringe

      ... Concentration=400 mcg/16mL
       =25 mcg/mL


  • 0.4 mg/mL (400 mcg/mL), ampoule


  1. McEvoy G K (ed): AHFS Drug Information, American Society of Hospital Pharmacists, 1991.
  2. Roberts, RJ: Drug Therapy in Infants, W.B. Saunders, Toronto, 1984.
  3. Gomella TL (Ed): Neonatology - Management, Procedures, On-Call Problems, Diseases, Drugs, 1992, Appleton and Lange, Norwalk, Connecticut.
  4. Young TE and Mangum OB: Neofax - A Manual of Drugs Used in Neonatal Care, Columbus, Ohio: Ross Laboratories, 1992.

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