Which antidote is used for reversing the effects of benzodiazepine overdose?

Flumazenil is the specific antidote used for reversing the effects of benzodiazepine overdose. It functions as a competitive antagonist at the benzodiazepine receptor site, thus blocking the action of benzodiazepines and reversing their sedative effects. This can be particularly useful in cases where the patient is overly sedated or experiencing respiratory depression due to an overdose of benzodiazepines.

In the context of the other options, naloxone is an opioid antagonist, primarily used for reversing opioid overdoses. Activated charcoal is a substance used to absorb toxins in the gastrointestinal tract but does not directly reverse drug effects; it must be administered within a certain time frame after ingestion to be effective. Atropine is an anticholinergic drug used in specific scenarios such as bradycardia or nerve agent poisoning but has no role in reversing benzodiazepine effects. Thus, flumazenil stands out as the targeted treatment for this particular situation.