Poison
Definition:
A poison is any substance that can cause harm or death when introduced into or absorbed by a living organism.
Sources:
Poisons can originate from chemicals, plants, animals, and medications.
Effects:
The impact of a poison depends on factors such as its nature, the amount absorbed, mode of exposure, and individual characteristics of the person exposed (age, health status, genetics).
Antidote
An antidote is a substance that counteracts the effects of a poison, reducing or eliminating the harm caused.
Mechanisms of Antidotes of Antidote
Neutralizing the Poison:
Directly neutralizes the poison’s effects.
Example: A weak base can neutralize strong acid ingestion.
Binding to the Poison:
Binds to the poison, rendering it inactive or less toxic.
Example: Activated charcoal absorbs and prevents the absorption of poisons in oral poisoning.
Enhancing Poison Elimination:
Increases the rate of poison elimination from the body.
Example: Chelating agents bind to heavy metals (e.g., lead, mercury) for excretion.
Reversing the Poison's Effects:
Reverses the physiological effects of the poison.
Example: Naloxone reverses respiratory depression caused by opioid overdose.
Providing an Essential Compound:
Supplies or mimics a compound depleted by the poison.
Example: Vitamin K is used to counteract warfarin poisoning by replenishing clotting factors.
Examples of Poisons and Their Antidotes
1) Acetaminophen (Tylenol) Overdose:
Antidote: N-acetylcysteine (NAC)
Action: Replenishes glutathione stores, helping to detoxify the harmful metabolite of acetaminophen.
2) Opioid Overdose:
Antidote: Naloxone
Action: Rapidly displaces opioids from their receptors, reversing effects, especially life-threatening respiratory depression.
3) Benzodiazepine Overdose:
Antidote: Flumazenil
Action: Blocks the effect of benzodiazepines on the GABA receptor, reversing sedation.
4) Organophosphate Poisoning (Certain Pesticides):
Antidotes: Atropine and Pralidoxime (2-PAM)
Action: Atropine relieves muscarinic symptoms, while pralidoxime reactivates acetylcholinesterase, which is inhibited by organophosphates.