Which antidote is used for Datura poisoning?

Physostigmine is the antidote used for Datura poisoning due to its ability to counteract the effects of anticholinergic toxicity. Datura species contain high levels of tropane alkaloids, primarily atropine and scopolamine, which exert anticholinergic effects by blocking acetylcholine at muscarinic receptors. This can lead to symptoms like dilated pupils, tachycardia, hallucinations, and altered mental status.

Physostigmine works by inhibiting acetylcholinesterase, the enzyme responsible for breaking down acetylcholine in the synapses. By doing this, it increases acetylcholine levels, thereby reversing the toxic effects induced by the anticholinergic agents found in Datura. It can effectively alleviate symptoms by reactivating cholinergic signaling in the central nervous system and peripheral nervous system, making it a specific antidote for this type of poisoning.

In contrast, other options are not suitable for treating Datura poisoning. Atropine, though it is an anticholinergic drug itself, would exacerbate the symptoms of Datura poisoning rather than alleviate them. Activated charcoal is generally used for gastrointestinal decontamination but does not counteract the physiological effects caused by the poison itself.