Antidote

A specific agent that counteracts a poison or medication overdose

Definition

An antidote is a substance that neutralizes, reverses, or counteracts the toxic effects of a specific poison, medication, or drug overdose. Timely recognition and administration of the correct antidote can be lifesaving.

Essential Antidotes

  • Acetaminophen: N-acetylcysteine (Mucomyst)
  • Warfarin: Vitamin K (phytonadione)
  • Heparin: Protamine sulfate
  • Opioids: Naloxone
  • Benzodiazepines: Flumazenil
  • Iron: Deferoxamine
  • Lead: EDTA, Succimer, Dimercaprol
  • Magnesium sulfate: Calcium gluconate
  • Digoxin: Digoxin immune Fab (Digibind)
  • Cyanide: Sodium thiosulfate, hydroxocobalamin
  • Organophosphates: Atropine + pralidoxime

Nursing Considerations

Identify toxic exposure early; note dose, time, route, and coingestions and follow institutional protocols. Consult Poison Control (1-800-222-1222 in U.S.). Monitor continuously for rebound toxicity if the antidote half-life is shorter than the substance's.

NCLEX Relevance

Memorize antidote pairings. Know that some poisons (methanol, ethylene glycol) use fomepizole as antidote.