Antidote

Antidote An antidote, from the Greek word 'antidote', meaning 'given as remedy' (maybe a drug or chelating agent or a chemical substance), is a remedy that relieves the toxic effect of biological (harmful secondary metabolites) or synthetic toxins. Antidotes are special pharmacological or toxicological agents that counteract the effect of a toxin or poison, either by binding and neutralizing the poison,preventing the absorption of the toxin, inhibiting the conversion of the toxin to more toxic metabolites, andantagonizing its end-organ effect. Broadly, antidotes transform the toxic substance kinetics or interfere with the effect of toxin at its receptor sites resulting in the exposure duration and alteration of toxin load. Reduction in active toxin can be achieved through specific binding for eliminating inert toxin-antidote complexes from the body, as in the cases using chelating agents for heavy metal poisoning, eg, hydroxocobalamin for cyanide poisoning. Activated charcoal is an example of a non-specific antidote used for lowering the concentration of ingested toxin through its high adsorption capacity, eliminating charcoal-bound toxin through feces, and interruptingentero-hepatic circulation.

Most antidotes are not cent percent effective as fatalities may still occur even when the antidote is given. Some antidotes are toxic themselves and should be used with caution. The benefit of antidotes is generally uncertain and time-dependent. Antidotes that decrease toxin levels must be given early, whereas that change the toxic metabolites or amend the effects could be administered at variable times.The antidote therapy duration depends on the consumed toxin type, route and estimated dose of exposure, clinical features of toxicity, and benefit vs.risk of using antidotes, etc. [Mamun Rashid Chowdhury]