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Introduction
- 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.
Indications
- 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
Contraindications
- Known hypersensitivity.
- Third-degree atrioventricular (AV) block.
- Patients with cardiac transplant.
Precautions / Notes
- 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.
Management
Symptomatic Bradycardia
Dilution: None
Adult:
- 0.6 mg in 0.5 mL IV/IO every 3-5 minutes titrated to effect.
- Maximum dose 3 mg
Paediatric:
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.
Maximum initial dose 1 mg.
Organophosphate poisoning
Dilution: Dilute 1.2 mg/1 mL with 11 mL saline for 1.2 mg/12 mL (100 microg/mL)
Adult:
- 1-2 mg (10-20mL) IV/IO, repeat every 5 minutes until atropinisation is evident
Paediatric:
- 0.02 mg/kg IV/IO, repeat every 5 minutes until atropinisation is evident
Paramedic Special Operations only
Adult:
- 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)
References
References
Presentation
1.2 mg / 1 mL ampoule
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