Pralidoxime

Pralidoxime is an antidote used for reversing organophosphate poisoning and acetylcholinesterase inhibitor toxicity (Neostigmine, Pyridostigmine).

• Pralidoxime is available under the following different brand names: Protopam, 2PAM Antidote, Pralidoxime Auto Injector.

Adult and pediatric dosage

Powder for reconstitution

• 1g/vial

Injection solution

• 300 mg/mL

Organophosphate Poisoning

Adult dosage

• 1-2 g IV infusion (10-20 mg/mL) over 15-30 minutes, repeat in 1 hour if necessary and repeat every 12 hours thereafter as needed; if not practical or if pulmonary edema is present or fluid restriction necessary administer as 50 mg/mL over 5 min; the second bolus of 1-2 g may be indicated after about 1 hour if muscle weakness has not been relieved; may repeat every 10-12 hours as needed
• Alternative, administer 30 mg/kg IV (IM, SC if no IV access) over 20 minutes; follow by 4-8 mg/kg/hour maintenance IV infusion
• Use with atropine, which affects muscarinic receptors; pralidoxime’s actions most striking at nicotinic sites (increase muscle strength 10-40 minutes)
• IM: 600 mg IM x 3 doses; administer each dose 15 minutes apart for mild symptoms, or in rapid succession for severe symptoms; not to exceed 1800 mg total dose initially; if symptoms persist may repeat series of three injections 1 hour after the last injection

Pediatric dosage 

• Children younger than 16 years of age
• 20-50 mg/kg/dose (not to exceed 2 g/dose) IV; followed by 10-20 mg/kg/hour IV continuous infusion for maintenance; alternatively may repeat bolus of 20-50 mg/kg/dose over 1 hour and repeat every 10-12 hours if muscle weakness has not been relieved 

Children older than 16 years of age

• 1-2 g IV infusion (10-20 mg/mL) over 15-30 min, repeat in 1 hour if necessary and repeat every 12 hours thereafter as needed; if not practical or if pulmonary edema present or fluid restriction necessary administer as 50 mg/mL over 5 minutes; the second bolus of 1-2 g may be indicated after about 1 hour if muscle weakness has not been relieved; may repeat every 10-12 hours as needed
• Alternatively, administer 30 mg/kg IV (IM, SC if no IV access) over 20 minutes; followed by 4-8 mg/kg/hour maintenance IV infusion

IM Administration

• Weightless than 40 kg: 15 mg/kg/dose IM x 3 doses administered every 15 minutes for mild symptoms; not to exceed 45 mg/kg or in rapid succession for severe symptoms
• Weight 40 kg or greater: 600 mg IM x 3 doses; administer each dose 15 minutes apart for mild symptoms, or in rapid succession for severe symptoms; not to exceed 1800 mg total dose initially
• If symptoms persist may repeat a series of three injections 1 hour after the last injection
• Administer in the anterolateral aspect of the thigh to avoid the nerve, artery, and vein, as well as the femur

Acetylcholinesterase Inhibitor Toxicity (Neostigmine, Pyridostigmine)

Adult dosage

• 1-2 g IV followed by 250 mg increments every 5 minutes as needed

Dosage Considerations – Should be Given as Follows: 

• See “Dosages”.

Common side effects of Pralidoxime include:

• pain at the injection site, 
• blurred vision, 
• dizziness, 
• drowsiness, 
• headache, and
• nausea 

Serious side effects of Pralidoxime include:

• hives, 
• difficulty breathing, 
• swelling of the face, lips, tongue, or throat, 
• fast heart rate, 
• rapid breathing, 
• increased muscle stiffness, and 
• choking feeling

Rare side effects of Pralidoxime include:

• none 

If your medical doctor is using this medicine to treat your pain, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider, or pharmacist first

• Pralidoxime has severe interactions with no other drugs. 
• Pralidoxime has serious interactions with the following drug:
  • pramlintide
• Pralidoxime has moderate interactions with at least 89 other drugs.
• Pralidoxime has minor interactions with the following drugs:
  • dimenhydrinate
  • donepezil
  • galantamine

This information does not contain all possible interactions or adverse effects. Visit the RxList Drug Interaction Checker for any drug interactions. Therefore, before using this drug, tell your doctor or pharmacist of all the drugs you use. Keep a list of all your medications with you, and share the list with your doctor and pharmacist. Check with your physician if you have health questions or concerns.

Contraindications

• None for the approved indications.

Effects of drug abuse

• None

Short-Term Effects

• See “What Are Side Effects Associated with Using Pralidoxime?”

Long-Term Effects

• See “What Are Side Effects Associated with Using Pralidoxime?”

Cautions

• Administer concomitant atropine
• Not approved for the treatment of carbamate poisoning
• Not indicated for poisoning resulting from inorganic phosphates, phosphorus, or organophosphates that do not involve anticholinesterase activity
• Use caution in myasthenia gravis (may precipitate myasthenia crisis)
• Not equally active against all organophosphates
• Give IM if the patient is cyanotic
• Observe patients for at least 24 hours

Pregnancy and Lactation

• Use with caution if the benefits outweigh the risks during pregnancy. 
• Lactation: No data available.