From the Guidelines
Continuous infusion of atropine is not recommended as a standard practice in most clinical settings, but it may be considered in rare circumstances such as severe organophosphate poisoning, where an infusion at 0.02-0.08 mg/kg/hr can be used after initial bolus dosing has achieved atropinization, as suggested by the 2023 American Heart Association guidelines 1. Atropine is typically administered as intermittent bolus doses of 0.5-1 mg IV every 3-5 minutes, up to a maximum of 3 mg in adults, rather than as a continuous infusion, according to the 2018 ACC/AHA/HRS guideline on the evaluation and management of patients with bradycardia and cardiac conduction delay 2, 3, 4. In rare circumstances where continuous anticholinergic effects are needed, atropine may be given as an infusion after initial bolus dosing has achieved atropinization. This approach requires close monitoring in an ICU setting with:
- Continuous cardiac monitoring
- Frequent vital sign checks
- Assessment for signs of atropine toxicity, including confusion, hyperthermia, urinary retention, flushing, and tachycardia. Some key points to consider include:
- The pharmacokinetics of atropine make bolus dosing more appropriate in most scenarios, as its effects typically last 4-6 hours, allowing for controlled titration based on clinical response.
- Alternative anticholinergic agents or different therapeutic approaches should be considered if prolonged therapy is required.
- The 2023 American Heart Association focused update on the management of patients with cardiac arrest or life-threatening toxicity due to poisoning provides guidance on the use of atropine in the context of organophosphate or carbamate poisoning 1.
From the FDA Drug Label
The FDA drug label does not answer the question.
From the Research
Continuous Infusion of Atropine
- The use of continuous atropine infusion has been studied in various medical contexts, including the management of severe tetanus 5 and organophosphorus poisoning 6.
- In the treatment of severe tetanus, continuous atropine infusion was found to maintain complete cardiovascular stability and prevent clinical symptoms such as bronchospasm and hypersalivation 5.
- In the treatment of organophosphorus poisoning, continuous intravenous infusion of atropine using a micropump was found to elevate the survival rate, reduce the incidence of adverse reactions, and shorten the reactivation time of cholinesterase 6.
- The effects of atropine on cardiac rhythm, heart rate, blood pressure, and airway secretion have also been studied, with findings suggesting that atropine can increase heart rate and blood pressure, but may not be necessary for routine use before mask anesthesia with isoflurane 7.
- Other studies have investigated the use of atropine in combination with other medications, such as vasopressors and inotropes, in the treatment of shock and cardiac critical care 8.
- The effects of large doses of intravenous atropine on heart rate and arterial pressure have also been studied, with findings suggesting that atropine can increase heart rate and systolic blood pressure in anesthetized patients 9.
Clinical Applications
- Continuous atropine infusion may be useful in the management of severe tetanus and organophosphorus poisoning, as well as in other medical contexts where anticholinergic therapy is indicated 5, 6.
- The use of atropine in combination with other medications, such as vasopressors and inotropes, may be beneficial in the treatment of shock and cardiac critical care 8.
- However, the routine use of atropine before mask anesthesia with isoflurane may not be necessary, due to the risk of tachycardia and other adverse effects 7.
Mechanisms of Action
- Atropine is a potent anticholinergic agent that can block the effects of acetylcholine on the heart, lungs, and other organs 5, 6.
- The mechanisms of action of atropine involve the inhibition of muscarinic receptors, which can lead to increased heart rate, decreased airway secretion, and other effects 7, 9.