What is the overdose treatment for antihistamines?

The appropriate treatment for an overdose of antihistamines is physostigmine. Antihistamines, particularly the first-generation types, can cause anticholinergic effects such as confusion, hallucinations, and severe drowsiness due to their acetylcholine receptor antagonism. Physostigmine is a reversible inhibitor of the enzyme acetylcholinesterase, which increases the availability of acetylcholine at the synaptic cleft. This can help counteract the anticholinergic symptoms by effectively reversing the overdose effects of these antihistamines.

It's worth noting that the other options, while applicable in their respective contexts, do not directly address the symptoms of antihistamine overdose. Naloxone is used for opioid overdoses, atropine could be used for some types of poisoning but is not indicated for antihistamine overdose specifically, and benzodiazepines are primarily used to manage anxiety and seizures but do not reverse the effect of antihistamines. Therefore, the choice of physostigmine is particularly significant in the context of treating the adverse effects associated with antihistamine toxicity.