From the Guidelines
Pralidoxime (PAM) is a crucial antidote for organophosphate (OP) poisoning, administered alongside atropine, with a recommended dosing of 1-2 g given intravenously over 15-30 minutes as a loading dose, followed by a continuous infusion of 400-600 mg/hour, as stated in the 2023 American Heart Association guidelines 1.
Key Considerations
- The dosing of pralidoxime may vary depending on the severity of the poisoning, with some cases requiring higher doses of up to 8-10 mg/kg/hour.
- Treatment should continue for at least 24 hours after symptoms resolve or until atropine is no longer needed.
- In resource-limited settings, intermittent dosing of 1-2 grams every 4-6 hours can be used.
- Pralidoxime works by reactivating acetylcholinesterase enzymes that have been inhibited by organophosphates, preventing the accumulation of acetylcholine at nerve junctions.
- For maximum effectiveness, pralidoxime should be administered as soon as possible after exposure, ideally within 24-48 hours, as the organophosphate-enzyme complex becomes irreversibly "aged" over time.
Administration and Side Effects
- Pralidoxime should always be given with atropine, which addresses the muscarinic symptoms of OP poisoning, while pralidoxime primarily addresses the nicotinic effects.
- Side effects may include dizziness, blurred vision, and occasional hypertension.
- The use of pralidoxime is reasonable for organophosphate poisoning, as stated in the 2023 American Heart Association guidelines 1.
Additional Recommendations
- Early and effective treatment may prevent deterioration to respiratory and cardiac arrest.
- The cornerstones of treatment include decontamination, atropine, benzodiazepines, and oximes.
- Dermal decontamination through removal of contaminated clothing and copious irrigation with soap and water, performed by people wearing protective barriers, helps prevent further absorption and prevents contamination of caregivers and the care environment, as recommended in the 2023 American Heart Association guidelines 1.
From the Research
Organophosphate Poisoning Overview
- Organophosphate (OP) compounds are common insecticides that can poison humans through accidental exposure or suicide attempts 2
- OP poisoning inhibits the activity of cholinesterase, leading to severe symptoms that may require intensive care support 2
Treatment and Management
- Treatment with intravenous atropine and pralidoxime is commonly used to manage OP poisoning 2, 3, 4, 5
- High-dose atropine therapy and early intervention are crucial in treating OP poisoning 5
- Pralidoxime is used to reactivate acetylcholinesterase, but its clinical benefit is still uncertain 3
- Whole-bowel irrigation with pralidoxime iodide may be an effective treatment approach in some cases 6
Complications and Outcomes
- Respiratory failure is a common complication of OP poisoning, with a high mortality rate 2
- Mechanical ventilation may be required in severe cases, with a mortality rate of 50% in one study 2
- The duration of intensive care stay can vary, with a mean stay of 7.1 days in one study 2
- The mortality rate for OP poisoning can range from 12.5% to 21%, depending on the treatment and severity of the poisoning 2, 4