Pralidoxime Chloride

Indications

Pralidoxime Chloride is used for: Organophosphorous poisoning

Adult Dose

Organophosphate Poisoning 1-2 g IV as 15-30 min infusion, repeat in 1 hr if necessary, OR 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 Acetylcholinesterase Inhibitor Toxicity Initial: 30 mg/kg IV (IM, SC if no IV access) over 20 min 4-8 mg/kg/hr IV infusion

Child Dose

Organophosphate Poisoning IV loading dose followed by continuous infusion 20-50 mg/kg/dose (not to exceed 2 g/dose) infused IV over 15-30 minutes Maintenance: 10-20 mg/kg/hr IV continuous infusion IV intermittent infusions 20-50 mg/kg (not to exceed 2 g/dose) IV infused over 15-30 minutes A second dose of 20-50 mg/kg may be indicated after about 1 hr if muscle weakness has not been relieved May repeat q10-12hr prn Other IV administration If it is not practical to administer intermittent or continuous IV infusions, or if pulmonary edema is present, the 20-50 mg/kg dose should be given slowly (infused over at least 5 minutes) by IV injection as a 50 mg/mL solution in water Additional doses may be given every 10-12 hours if muscle weakness persists IM administration <40 kg: 15 mg/kg/dose IM x3 doses 40 kg or greater: Administer as in adults; 600 mg/dose IM x3 doses Administer each dose 15 minutes apart for mild symptoms, or in rapid succession for severe symptoms Administer in the anterolateral aspect of the thigh to avoid the nerve, artery and vein, as well as the femur

Renal Dose

Renal Impairment: Reduce dose

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) 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

Contra Indications

Carbamate pesticide poisoning, hypersensitivity.

Precautions

Renal dysfunction, myasthenia gravis. Atropinisation may occur faster when atropine and pralidoxime are used together. Pregnancy, lactation.

Pregnancy-Lactation

Interactions

Adverse Effects

Side effects of Pralidoxime Chloride : Drowsiness, dizziness, visual disturbances, nausea, tachycardia, headache, hyperventilation and muscle weakness. Potentially Fatal: Rapid admin causes tachycardia, laryngospasm and rigidity. Large doses cause neuromuscular blockade.

Mechanism of Action

Pralidoxime reactivates cholinesterase outside the CNS which has been inactivated by phosphorylation due to organophosphate pesticide exposure-resulting. This leads to the destruction of acetylcholine at the neuromuscular junction thus relieving muscle paralysis. It also removes the phosphyl group from the active site of inactivated enzyme which is dependent on the nature of the phosphyl group.