Core pharmacology

Class Group

Antidote

Legacy Cicm Level

Level 3

Indications Uses

- Organophosphate poisoning
- Acetylcholinesterase Inhibitor toxicity (Neostigmine, Pyridostigmine)

Chemical Pharmaceutics

Synthetic oxime of Pyridine-2-carboxaldehyde

Presentation

IV: Reconstituted 1gm solution
IM: auto-injector 600mg/2ml

Main Action

antidote to organophosphate

Mechanism of action

reactivator of phosphorylated Acetylcholinesterase by promoting hydrolysis

Onset Peak Duration

Onset: 5-15 min

Adverse Effects Toxicity

Cardiac arrest, hypertension, tachycardia
muscle rigidity, weakness
Transient transaminitis

Absorption

-

Protein binding

None

Volume of distribution

0.6-2.7 L/kg
may increase in severe organophosphate intoxication

Metabolism

Liver

Excretion

Urine: 80% metabolites + unchanged

Half-life

3-4 hr (IM, IV)

Route And Dose

IV/IM/SC

OP poisoning:
30 mg/kg IV (max 2gm) (600mg IM every 15min upto 1.8gm, SC if no IV access) over 20 min; follow by 8-10 mg/kg/hr (max 650mg) maintenance IV infusion

Acetylcholinesterase Inhibitor Toxicity: (Neostigmine, Pyridostigmine)
1-2 g IV followed by 250 mg increments q5min PRN