Dosing & Uses
Dosage Forms & Strengths
powder for reconstitution
- 1g/vial
injection solution
- 300 mg/mL
Organophosphate Poisoning
1-2 g IV infusion (10-20 mg/mL) over 15-30 min, repeat in 1 hr if necessary and repeat q12hr thereafter PRN; if not practical or if pulmonary edema present or fluid restriction necessary administer as 50 mg/mL over 5 min; a second bolus of 1-2 g may be indicated after about 1 hr if muscle weakness has not been relieved; may repeat q10-12hr prn
Alternatively, administer 30 mg/kg IV (IM, SC if no IV access) over 20 min; follow by 4-8 mg/kg/hr maintenance IV infusion
Use with atropine, which affects muscarinic receptors; pralidoxime's actions most striking at nicotonic sites (increase muscle strength 10-40 min)
IM: 600 mg IM x3 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 hr after last injection
Acetylcholinesterase Inhibitor Toxicity (Neostigmine, Pyridostigmine)
1-2 g IV followed by 250 mg increments q5min PRN
Renal Impairment
Reduce dose; no specific recommendations provided by manufacturer
Dosage Forms & Strengths
powder for reconstitution
- 1g/vial
injection solution
- 300 mg/mL
Organophosphate Poisoning
< 16 years
- 20-50 mg/kg/dose (not to exceed 2 g/dose) IV; follow by 10-20 mg/kg/hr IV continuous infusion for maintenance; alternatively may repeat bolus of 20-50 mg/kg/dose over 1 hr and repeat q10-12hr if muscle weakness has not bee relieved
> 16 years
- 1-2 g IV infusion (10-20 mg/mL) over 15-30 min, repeat in 1 hr if necessary and repeat q12hr thereafter PRN; if not practical or if pulmonary edema present or fluid restriction necessary administer as 50 mg/mL over 5 min; a second bolus of 1-2 g may be indicated after about 1 hr if muscle weakness has not been relieved; may repeat q10-12hr prn
- Alternatively, administer 30 mg/kg IV (IM, SC if no IV access) over 20 min; follow by 4-8 mg/kg/hr maintenance IV infusion
IM administration
- <40 kg: 15 mg/kg/dose IM x3 doses administered q15min for mild symptoms; not to exceed 45 mg/kg or in rapid succession for severe symptoms
- >40 kg or greater: 600 mg IM x3 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 hr after last injection
- Administer in the anterolateral aspect of the thigh to avoid the nerve, artery and vein, as well as the femur
Administer with caution; consider possibility of decreased renal, hepatic, and renal function
Interactions
Interaction Checker
No Results
Contraindicated
Serious - Use Alternative
Significant - Monitor Closely
Minor
Adverse Effects
Frequency Not Defined
Pain at site
Transient dizziness
Blurred vision
Double vision
Dizziness
Hypertension
Tachycardia
Cardiac arrest
Laryngospasm
Muscle rigidity
ALT (transient increase); AST (transient increase)
Respiratory/cardiac arrest if given too fast IV
Headache
Seizure
Drowsiness
Nausea
Warnings
Contraindications
None for the approved indications
Cautions
Administer concomitant atropine
Not approved for the treatment of carabamate poisoning
Not indicated for poisoning resulting from inorganic phosphates, phosphorus, or organophosphates that do not involve anticholinesterase activity
Use caution in myasthenia gravis (may presipitate myasthenia crisis)
Not equally active against all organophosphates
Give IM if patient is cyanotic
Observe patients for at least 24 hr
Pregnancy & Lactation
Pregnancy Category: C
Pregnancy Categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk. C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done. D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk. X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist. NA: Information not available.Pharmacology
Mechanism of Action
Binds to organophosphates and breaks alkyl phosphate-cholinesterase bond to restore activity of acetylcholinesterase
Pharmacokinetics
Onset: 5-15 min
Vd: 0.6-2.7 L/kg (may increase in severe organophosphate intoxication)
Protein binding: None
Metabolism: Hepatic
Half-life: 3-4 hr (IM, IV)
Excretion: 80%
Administration
IV Preparation
Reconstitute by adding 20 mL SWI to the 1 g vial to provide a 50 mg/mL solution (do not use preservative-containing solutions)
Use within a few hours
IV Administration
For infusion, dilute required amount of reconstituted solution to 100 mL with NS
Infuse over 15-30 min
May also be given as 5 min slow IVP
IM Administration
1 g vial contents may be reconstituted by adding 3 mL SWI or NS to provide a 300 mg/mL solution
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Patient Handout
Formulary
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