Definition
An antidote is a substance which counteracts, neutralizes, prevents, or diminishes the effects of a poison.
Classification of Antidotes
There are four classes: Physical, Chemical, Physiological, and Chelating agents.
1. Physical (Mechanical) Antidotes
Act by preventing absorption of the poison without chemically altering it.
- Mechanism: adsorption, coating, dilution.
- Examples: activated charcoal, milk, egg albumin.
2. Chemical Antidotes
Act by chemically reacting with the poison to form a harmless or less toxic compound.
| Poison | Chemical Antidote |
|---|---|
| Arsenic | Ferric hydroxide |
| Cyanide | Sodium nitrite + Sodium thiosulphate |
| Heavy metals | Chelating agents |