Cardiovascular: Tachycardia, hypertension

Central nervous system: Dizziness, headache, drowsiness

Dermatologic: Rash

Gastrointestinal: Nausea

Hepatic: Transient increases in ALT, AST

Local: Pain at injection site after I.M. administration

Neuromuscular & skeletal: Muscle rigidity, weakness

Ocular: Accommodation impaired, blurred vision, diplopia

Renal: Renal function decreased

Respiratory: Hyperventilation, laryngospasm

Decreased effect: Atropine, although often used concurrently with pralidoxime to offset muscarinic stimulation, these effects can occur earlier than anticipated

Increased effect: Barbiturates (potentiated)

Increased toxicity: Use with aminophylline, morphine, theophylline, and succinylcholine is contraindicated; use with reserpine and phenothiazines should be avoided in patients with organophosphate poisoning

Protein binding: None

Metabolism: Hepatic

Half-life elimination: 74-77 minutes

Time to peak, serum: I.V.: 5-15 minutes

Excretion: Urine (80% to 90% as metabolites and unchanged drug)

Organic phosphorus poisoning (use in conjunction with atropine; atropine effects should be established before pralidoxime is administered): I.V. (may be given I.M. or SubQ if I.V. is not feasible):

Children: 20-50 mg/kg/dose; repeat in 1-2 hours if muscle weakness has not been relieved, then at 8- to 12-hour intervals if cholinergic signs recur

Adults: 1-2 g; repeat in 1 hour if muscle weakness has not been relieved, then at 8- to 12-hour intervals if cholinergic signs recur. When the poison has been ingested, continued absorption from the lower bowel may require additional doses; patients should be titrated as long as signs of poisoning recur; dosing may need repeated every 3-8 hours.

Treatment of acetylcholinesterase inhibitor toxicity: Adults: I.V.: Initial: 1-2 g followed by increments of 250 mg every 5 minutes until response is observed

Nerve agent toxicity management (unlabeled use): Note: Atropine is a component of the management of nerve agent toxicity; consult atropine monograph for specific route and dose. To be effective, pralidoxime must be administered within minutes to a few hours following exposure (depending on the nerve agent).

Infants and Children:

Prehospital ("in the field"): Mild-to-moderate symptoms: I.M.: 15 mg/kg; severe symptoms: 25 mg/kg

Hospital/emergency department: Mild-to-severe symptoms: I.V.: 15 mg/kg (up to 1 g)

Adults:

Prehospital ("in the field"): Mild-to-moderate symptoms: I.M.: 600 mg; severe symptoms: 1800 mg

Hospital/emergency department: Mild-to-severe symptoms: I.V.: 15 mg/kg (up to 1 g)

Frail patients, elderly:

Prehospital ("in the field"): Mild-to-moderate symptoms: I.M.: 10 mg/kg; severe symptoms: 25 mg/kg

Hospital/emergency department: Mild-to-severe symptoms: I.V.: 5-10 mg/kg

Elderly: Refer to Adults dosing; dosing should be cautious, considering possibility of decreased hepatic, renal, or cardiac function

Dosing adjustment in renal impairment: Dose should be reduced

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Farrar HC, Wells TG, and Kearns GL, "Use of Continuous Infusion of Pralidoxime for Treatment of Organophosphate Poisoning in Children,"J Pediatr, 1990, 116(4):658-61.

Jovanovic D, "Pharmacokinetics of Pralidoxime Chloride. A Comparative Study in Healthy Volunteers and in Organophosphorus Poisoning,"Arch Toxicol, 1989, 63(5):416-8.

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"Medical Management Guidelines (MMGs) for Nerve Agents: Tabun (GA); Sarin (GB); Soman (GD); and VX." Available at: www.atsdr.cdc.gov/MHMI/mmg166.html. Accessed January 8, 2003.

Medicis JJ, Stork CM, Hoffman RS, et al, "Improved 2-PAM Dosing Regimen in Human Volunteers: A Pharmacokinetic Study,"Vet Hum Toxicol, 1994, 36:377.

Mokhlesi B, Leikin JB, Murray P, et al, "Adult Toxicology in Critical Care: Part II: Specific Poisonings,"Chest, 2003, 123(3):897-922.

Murphy M and Desai H, "Pralidoxime-Induced Laryngospasm,"Vet Hum Toxicol, 1994, 36:375.