From the Guidelines
The use of pralidoxime is reasonable for organophosphate poisoning.
Key Points
- The American Heart Association recommends the use of pralidoxime for organophosphate poisoning, with a suggested initial dose of 1-2 g and a maintenance infusion of 400-600 mg/h for adults 1.
- The dose for pediatric patients is 20-50 mg/kg with a maintenance infusion of 10-20 mg/kg/h 1.
- Pralidoxime works by reactivating the acetylcholinesterase enzyme, reversing nicotinic effects to improve respiratory and skeletal muscle strength, although this effect may be organophosphate specific 1.
- It is essential to note that the available data are not sufficient to support a recommendation for or against oxime use in carbamate poisoning, but oximes should not be withheld in cases of cholinesterase poisoning when the class of poison is unknown 1.
From the FDA Drug Label
The principal action of pralidoxime chloride is to reactivate cholinesterase (mainly outside of the central nervous system) which has been inactivated by phosphorylation due to an organophosphate pesticide or related compound. Regardless of whether or not animal studies suggest that the organophosphate poison to which a particular patient has been exposed is amenable to treatment with pralidoxime chloride, the use of pralidoxime chloride should, nevertheless, be considered in any life-threatening situation resulting from poisoning by these compounds, since the limited and arbitrary conditions of pharmacologic screening do not always accurately reflect the usefulness of pralidoxime chloride in the clinical situation.
The correct statement regarding the use of pralidoxime (2-PAM) for organophosphate poisoning is that pralidoxime chloride should be considered in any life-threatening situation resulting from poisoning by these compounds.
- Key points:
- Pralidoxime chloride reactivates cholinesterase inactivated by organophosphate poisoning.
- Its use should be considered in life-threatening situations, regardless of the specific poison.
- Pralidoxime chloride is relatively short-acting and repeated doses or continuous infusion may be necessary 2.
From the Research
Use of Pralidoxime in Organophosphate Poisoning
- The efficacy of pralidoxime in the treatment of organophosphate poisoning is uncertain, with some studies suggesting it may not provide significant improvement in outcome and may even cause harm 3, 4.
- A systematic review and meta-analysis of randomized trials found that pralidoxime was not shown to be beneficial in patients with acute organophosphate poisoning, with a significant increase in the incidence of intermediate syndrome in the pralidoxime group 3.
- Another study found that oximes, including pralidoxime, may be irrelevant in the treatment of organophosphate poisoning, particularly in cases of self-poisoning typical of tropical regions 4.
- A prospective analysis of organophosphorus poisoning cases found that only 33% of cases with pseudocholinesterase levels less than 10% were treated with pralidoxime, and the doses prescribed were less than the WHO-recommended doses 5.
- A study on the regeneration of red cell cholinesterase activity following pralidoxime infusion found that the maximum increase in activity occurred in the first 4 hours of administration, followed by a slow increase despite continued infusion 6.
- A randomized clinical trial found that add-on pralidoxime therapy did not offer any appreciable benefit over atropine alone in terms of reducing mortality and ventilator requirement, but was associated with a longer duration of hospital stay 7.
Key Findings
- Pralidoxime may not provide significant improvement in outcome for patients with organophosphate poisoning 3, 7.
- The use of pralidoxime may be associated with an increased incidence of intermediate syndrome 3.
- The efficacy of pralidoxime in organophosphate poisoning is uncertain and requires further study 4, 7.
- The dosing regimen of pralidoxime may be an important factor in its efficacy, with some studies suggesting that higher doses may be more effective 5, 6.