Oxime Reactivation
Definition
Restoration of acetylcholinesterase function by pralidoxime (2-PAM) or obidoxime through cleavage of the organophosphate-enzyme bond, effective only before the enzyme is irreversibly aged, broadly within 24 to 36 hours of exposure.
- Agents used
- Pralidoxime (2-PAM) or obidoxime
- Mechanism
- Cleaves the organophosphate-enzyme bond
- Target enzyme
- Acetylcholinesterase
- Effective window
- Roughly 24 to 36 hours before enzyme 'aging'
Common questions
What happens if oxime therapy is given after the enzyme has aged?+
Once the organophosphate-enzyme bond has aged, it becomes resistant to cleavage and oxime reactivation no longer restores enzyme function, so treatment beyond the effective window relies on supportive care and atropine rather than oxime alone.
Why is oxime reactivation given alongside atropine rather than by itself?+
Atropine blocks the effects of excess acetylcholine at receptor sites and provides immediate symptom control, while oxime works separately to restore the enzyme itself, so the two are used together to address different parts of organophosphate toxicity.
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