Which of the following is NOT an antidote mentioned for any agents?

Activated charcoal is not considered an antidote in the traditional sense, as it does not neutralize or counteract the effects of specific toxins or drugs. Instead, activated charcoal is used in the context of poisonings to absorb substances in the gastrointestinal tract, thus preventing their absorption into the bloodstream. It acts as a protective measure rather than a treatment for toxicity itself.

In contrast, sodium bicarbonate (bicarb) is used in cases of certain drug overdoses, particularly tricyclic antidepressants, to help manage metabolic acidosis and improve the elimination of these drugs. Pyridoxine is utilized as an antidote for specific poisoning cases, particularly in the context of isoniazid overdose, where it helps to reverse the toxic effects. Acetadote, or N-acetylcysteine, is a well-known antidote for acetaminophen overdose, effectively preventing liver damage when given in a timely manner.

Thus, activated charcoal's role is distinct from that of true antidotes, aligning with why it is the choice that is not considered an antidote like the others mentioned.