What is the intravenous (IV) atropine dose in organophosphate (OP) poisoning?

From the Guidelines

In OP poisoning, atropine should be administered intravenously starting with 1-2 mg bolus for adults, doubled every 5 minutes until signs of atropinization appear, and maintained with a continuous infusion at 10-20% of the total loading dose per hour, as recommended by the 2023 American Heart Association guidelines 1. The initial dose of atropine for OP poisoning in adults is 1-2 mg, which can be doubled every 5 minutes until the desired effect is achieved, with a maintenance infusion of 10%–20% of the total loading dose per hour up to 2 mg/h, as outlined in the guidelines 1.

• Key considerations for atropine administration in OP poisoning include:
  • Initial dose: 1-2 mg for adults, 0.02 mg/kg for pediatrics
  • Dosing interval: every 5 minutes, doubling the dose until atropinization is achieved
  • Maintenance infusion: 10-20% of the total loading dose per hour
  • Monitoring for signs of atropinization, such as dry mucous membranes, decreased bronchial secretions, and heart rate >80 beats per minute Atropine therapy should be accompanied by other treatments, such as oximes (like pralidoxime) and proper airway management and respiratory support as needed, to address the full spectrum of OP poisoning effects, as supported by the guidelines 1.

From the FDA Drug Label

Antidote for organophosphorus or muscarinic mushroom poisoning: Initial single dose of 2 to 3 mg, repeated every 20 to 30 minutes. The recommended IV atropine dose for organophosphorus (OP) poisoning is an initial single dose of 2 to 3 mg, which may be repeated every 20 to 30 minutes 2.

• The dose should be titrated according to heart rate, PR interval, blood pressure, and symptoms.
• Key considerations for atropine administration include tachycardia, glaucoma, pyloric obstruction, urinary retention, and viscid bronchial plugs.

From the Research

IV Atropine Dose in OP Poisoning

• The optimal dose of IV atropine for organophosphate (OP) poisoning is not explicitly stated in the provided studies, but it is mentioned that atropine is a crucial medication in the treatment of OP poisoning 3, 4.
• A study published in 2014 reported that the highest dose of atropine given was 100 mg intravenously on admission and 100 mg/h/day during follow-up, with a total dose of 11.6 g/12 days 4.
• Another study from 1997 mentioned that atropine sulfate was administered intermittently, but the exact dose was not specified 5.
• The use of pralidoxime, an oxime, in conjunction with atropine is also discussed in the studies, but its efficacy is still uncertain 6, 7.
• A systematic review and meta-analysis published in 2020 found that pralidoxime was not shown to be beneficial in patients with acute OP poisoning and may even cause harm 7.

Treatment Approaches

• The studies suggest that treatment of OP poisoning should involve early diagnosis, careful monitoring, and appropriate management of complications 3, 4.
• High-dose atropine therapy and early intervention are recommended, and novel treatment approaches such as hemofiltration and lipid solutions have been studied 4.
• Continuous infusion of pralidoxime has been used in some cases to manage prolonged nicotinic symptoms, but its efficacy and safety are still uncertain 5.