Toxicity
An acute anticholinergic syndrome is reversible and subsides once all of the causative agents have been excreted. Reversible acetylcholinesterase inhibitor agents such as physostigmine can be used as an antidote in life-threatening cases. Wider use is discouraged due to the significant side effects related to cholinergic excess including seizures, muscle weakness, bradycardia, bronchoconstriction, lacrimation, salivation, bronchorrhea, vomiting, and diarrhea. Even in documented cases of anticholinergic toxicity, seizures have been reported after the rapid administration of physostigmine. Asystole has occurred after physostigmine administration for tricyclic antidepressant overdose, so a conduction delay (QRS > 0.10 second) or suggestion of tricyclic antidepressant ingestion is generally considered a contraindication to physostigmine administration. Pharmacology
Anticholinergics are classified according to the receptors that are affected:

Antimuscarinic agents operate on the muscarinic acetylcholine receptors. The majority of anticholinergic drugs are antimuscarinics. Antinicotinic agents operate on the nicotinic acetylcholine receptors. The majority of these are non-depolarising skeletal muscle relaxants for surgical use that are structurally related to curare. Several are depolarizing agents. Examples
Examples of common anticholinergics:

Plants of the family Solanaceae contain various anticholinergic tropane alkaloids, such as scopolamine, atropine, and hyoscyamine. Physostigmine is one of only a few drugs that can be used as an antidote for anticholinergic poisoning. Nicotine also counteracts anticholinergics by activating nicotinic acetylcholine receptors. Caffeine (although an adenosine receptor antagonist) can counteract the anticholinergic symptoms by reducing sedation and increasing acetylcholine activity, thereby causing alertness and arousal. Psychoactive uses
When a significant amount of an anticholinergic is taken into the body, a toxic reaction known as acute anticholinergic syndrome may result.
Hennekam syndrome also known as intestinal lymphagiectasia–lymphedema–mental retardation syndrome, is an autosomal recessive disorder consisting  of intestinal lymphangiectasia, facial anomalies, peripheral lymphedema, and mild to moderate levels of growth and intellectual disability.It is also known as "lymphedema-lymphangiectasia-mental retardation syndrome".Hennekam Syndrome is subdivided according to the causative genetic lesion, most (or all) of which are affecting the VEGF-C/VEGFR-3 signaling pathway:

Type 1 (mutations in CCBE1) 
Type 2 (mutations in FAT4)
Type 3 (mutations in ADAMTS3)The first recognition of a genetic association was with CCBE1, published by its namesake, Raoul Hennekam. The molecular mechanism of the lymphedema phenotype in CCBE1-associated cases was identified as a diminished ability of the mutated CCBE1 to accelerate and focus the activation of the primary lymphangiogenic growth factor VEGF-C. Mutations in the FAT4 gene had previously been only associated with van Maldergem syndrome, but the pathogenetic molecular mechanism and the function of FAT4 within lymphangiogenesis are still unknown. References


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