• An anticholinergic agent that inhibits the action of acetylcholine on post ganglionic nerves at the neuroeffector site. This blocks vagal stimulation to allow the sympathetic response to increase pulse rate by increasing SA node firing rate, and increasing the conduction velocity through the AV node.
  • An antidote to reverse the effects of cholinesterase inhibitors such as seen with organophosphate poisoning.
  • Symptomatic Bradycardia, haemodynamically unstable due to the bradycardia and associated with poor signs of perfusion, including:
    • Hypotension
    • Altered conscious state
    • Diaphoresis
    • Shortness of breath, and/or cyanosis
    • Syncope
  • Organophosphate poisoning with cholinergic effects
  • Known hypersensitivity.
  • Patients with cardiac transplant.
 Precautions / Notes
  • Atropine may not be effective in patients in third-degree atrioventricular (AV) block.
  • Isolated Bradycardia or link to traumatic cause is not an indication for atropine. All reversible causes should be addressed prior to consideration of Atropine.
  • It is advisable that a 12 Lead ECG is conducted prior to medication administration to rule out Acute Myocardial Infarction (STEMI) and Third-degree atrioventricular (AV) block.
    • If in doubt transmit 12-lead ECG to CSP SOC to discuss, or seek ASMA advice.
  • Bradycardia in children is usually a result of hypoxia or vagal stimulation. Ensure all reversible causes addressed and consider commencing resuscitation as per CPG if unresponsive.
  • Atropine may affect patients with glaucoma.
  • The maximum dose of Atropine that has shown to produce the desired effect in healthy adults is up to 3mg for bradycardia. In organophosphate poisoning: atropinisation might require significant repeat dosages and is achieved when with an increased HR, dilated pupils and decreased secretion, do not delay transport as atropinisation might not be achievable in the pre-hospital setting.

Symptomatic Bradycardia:

  • Do not dilute

Organophosphate poisoning

  • Dilute 1.2 mg/1 mL with 11 mL saline for 1.2 mg/12 mL (100 microg/mL)
 Weight-based Calculations
IV Atropine for organophosphate poisoning
Presentation: 1.2mg:12mL (0.1mg/mL)
Calculated dose:  to  in  to 
IV Atropine for symptomatic bradycardia
Presentation: /mL
Calculated dose:  in
For paediatric patients the following applies
AP: ASMA Consult Required
CCP: Authorised to Administer

Symptomatic Bradycardia


  • 0.6 mg in 0.5 mL IV/IO every 3-5 minutes titrated to effect.
  • Maximum dose 3 mg


    Ambulance Paramedic
    ASMA Consult required.
    Critical Care Paramedic
    0.02 mg/kg IV/IO (minimum dose 0.01 mg/kg)
    Maximum initial dose 1 mg.
Organophosphate poisoning


  • 1-2 mg (10-20mL) IV/IO, repeat every 5 minutes until atropinisation is evident


  • 0.02 mg/kg IV/IO, repeat every 5 minutes until atropinisation is evident
Paramedic – Special Operations


  • Initial dose: 1.2 mg IV/IO
  • Repeat dose: Sequential doubling increasing repeat doses (2.4 mg, 4.8 mg, 9.6 mg, etc…) every 3-5 minutes until atropinisation is evident.
Initial Dose 1st Repeat 2nd Repeat 3rd Repeat 4th Repeat 5th Repeat
1.2 mg/1 mL 2.4 mg/2 mL 4.8mg/4mL 9.6 mg/8 mL 19.2 mg/16 mL 38.4 mg/32 mL
Total Dose 3.6 mg/3 mL 8.4mg/7mL 18 mg/15 mL 37.2 mg/31 mL 75.6 mg/63 mL
 Special Considerations
  • Tachycardia and/or palpitations
  • Dilated pupils and/or blurred vision
  • Dry mouth and/or urinary retention
  • Confusion, restlessness (large doses)
  • Hot, dry skin (large doses)
1.2 mg / 1 mL ampoule
Current mode:
Extended Care:
Colour assist:


Document Control

Clinical Services

Responsible Manager
Head of Clinical Services


Issue Date

Expiry Date

Clinical Resources Website

St John Ambulance Western Australia Ltd (ABN 55 028 468 715) (St John WA) operates ambulance and other pre-hospital clinical services. St John WA’s Clinical Resources, including its Clinical Practice Guidelines (Clinical Resources), are intended for use by credentialed St John WA staff and volunteers when providing clinical care to patients for or on behalf of St John WA, within the St John WA Clinical Governance Framework, and only to the extent of the clinician’s authority to practice.

Other users – Terms of Use

The content of the St John WA Clinical Resources is provided for information purposes only and is not intended to serve as health, medical or treatment advice. Any user of this website agrees to be bound by these Terms of Use in their use of the Clinical Resources.

St John WA does not represent or warrant (whether express, implied, statutory, or otherwise) that the content of the Clinical Resources is accurate, reliable, up-to-date, complete or that the information contained is suitable for your needs or for any particular purpose. You are responsible for assessing whether the information is accurate, reliable, up-to-date, authentic, relevant, or complete and where appropriate, seek independent professional advice.

St John WA expressly prohibits use of these Clinical Resources to guide clinical care of patients by organisations external to St John WA, except where these organisations have been directly engaged by St John WA to provide services. Any use of the Clinical Resources, with St John WA approval, must attribute St John WA as the creator of the Clinical Resources and include the copyright notice and (where reasonably practicable) provide a URL/hyperlink to the St John WA Clinical Resources website. 

No permission or licence is granted to reproduce, make commercial use of, adapt, modify or create derivative works from these Clinical Resources. For permissions beyond the scope of these Terms of Use, including a commercial licence, please contact medservices@stjohnambulance.com.au

Where links are provided to resources on external websites, St John WA:

  • Gives no assurances about the quality, accuracy or relevance of material on any linked site;
  • Accepts no legal responsibility regarding the accuracy and reliability of external material; and
  • Does not endorse any material, associated organisation, product or service on other sites.

Your use of any external website is governed by the terms of that website, including any authorisation, requirement or licence for use of the material on that website.

To the maximum extent permitted by law, St John WA excludes liability (including liability in negligence) for any direct, special, indirect, incidental, consequential, punitive, exemplary or other loss, cost, damage or expense arising out of, or in connection with, use or reliance on the Clinical Resources (including without limitation any interference with or damage to a user’s computer, device, software or data occurring in connection with such use).


Please read this cookie policy carefully before using Clinical Resources from St John WA.

The cookies used on this site are small and completely anonymous pieces of information and are stored on your computer or mobile device. The data that the cookies contain identify your user preferences (such as your preferred text size, scope / skill level preference and Colour Assist mode, among other user settings) so that they can be recalled the next time that you visit a page within Clinical Resources. These cookies are necessary to offer you the best and most efficient possible experience when accessing and navigating through our website and using its features. These cookies do not collect or send analytical information back to St John WA.

Clinical Resources does integrate with Google Analytics and any cookies associated with this service enable us (and third-party services) to collect aggregated data for statistical purposes on how our visitors use this website. These cookies do not contain personal information such as names and email addresses and are used to help us improve your user experience of the website.

If you want to restrict or block the cookies that are set by our website, you can do so through your browser setting. Alternatively, you can visit www.internetcookies.com, which contains comprehensive information on how to do this on a wide variety of browsers and devices. You will find general information about cookies and details on how to delete cookies from your device. If you have any questions about this policy or our use of cookies, please contact us.

St John Ambulance Western Australia Ltd © Copyright 2020, All Rights Reserved

Terms of Use | Privacy Policy | Copyright Statement & Disclaimer