View source for Anticholinergic

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==Overview==
An '''anticholinergic''' agent is a member of a class of [[pharmaceutical]] compounds (such as Dicyclomine) which serve to reduce the effects mediated by [[acetylcholine]] in the central nervous system and [[peripheral nervous system]].

Anticholinergics are typically reversible [[competitive inhibitor]]s of one of the two types of acetylcholine [[transmembrane receptor|receptors]], and are classified according to the receptors that are affected: 

* ''[[antimuscarinic]]'' agents operate on the [[muscarinic acetylcholine receptor]]s. (The majority of anticholinergics are antimuscarinics.)
* ''[[antinicotinic]]'' agents operate on the [[nicotinic acetylcholine receptor]]s. 

==Effects==
When a significant amount of anticholinergic is taken into the body, a [[toxidrome]] known as '''acute anticholinergic syndrome''' may result.  This may happen accidentally or intentionally as a form of [[recreational drug use]].  This class of drug is usually considered the least "fun" by experienced drug users, possibly due to the lack of euphoria caused by anticholinergics.  Because most users do not enjoy the experience, they do not use it again, or very rarely.  Risk of addiction is low in the anticholinergic class.  Effects are usually more pronounced in the elderly, due to the decrease of acetylcholine production associated with age.

Possible effects of anticholinergics include:
*[[Ataxia]]; loss of coordination
*Decreased mucus production in the nose and [[throat]]; consequent dry, sore throat
*[[Xerostomia]] or dry mouth
*Cessation of [[perspiration]]; consequent increased thermal dissipation through the skin leading to hot, red skin
*Increased [[body temperature]]
*Pupil dilation ([[mydriasis]]); consequent sensitivity to bright light ([[photophobia]])
*Loss of accommodation (loss of focusing ability, blurred vision &mdash; [[cycloplegia]])
*Double vision ([[diplopia]])
*Increased heart rate ([[tachycardia]])
*[[Urinary retention]]
*Diminished bowel movement, sometimes [[ileus]]
*Increased [[intraocular pressure]], dangerous for people with narrow-angle [[glaucoma]]
*Shaking

Possible effects in the [[central nervous system]] resemble those associated with [[delirium]], and may include:
*Confusion
*Disorientation
*Agitation
*Respiratory depression
*Short-term memory loss
*Inability to concentrate
*Wandering thoughts; inability to sustain a [[train of thought]]
*Incoherent speech
*Wakeful [[myoclonic jerk]]ing
*Unusual sensitivity to sudden sounds
*Illogical thinking
*Photophobia
*Visual disturbances
**Periodic flashes of light
**Periodic changes in visual field
**Visual snow
**Restricted or "tunnel vision"
*Visual, auditory, or other sensory [[hallucination]]s
**Warping or waving of surfaces and edges
**Textured surfaces
**"Dancing" lines; "spiders", insects
**Lifelike objects indistinguishable from reality
*Rarely: seizures, coma and death

Acute anticholinergic syndrome is completely reversible and subsides once all of the toxin has been excreted.  Ordinarily, no specific treatment is indicated.  However, in extreme cases, especially those that involves severe distortions of mental state, a reversible [[cholinergic]] agent such as [[physostigmine]] may be used.

==Plant sources==
The most common plants containing anticholinergic alkaloids are:
*''Atropa belladonna'' (Deadly Nightshade)
*''Mandragora officinarum'' (Mandrake)
*''[[Henbane|Hyoscamus niger]]'' (Henbane)
*''[[Datura]]'' species (Datura)

==Abuse==
Some drugs, such as [[hydrocodone]], are mixed with small amounts of an anticholinergic, such as [[Homatropine Methylbromide]] to discourage [[drug abuse|abuse]].


{{Drugs for functional gastrointestinal disorders}}
{{Urologicals}}
{{Muscle relaxants}}
{{Anti-parkinson anticholinergic agents}}
{{Asthma and copd rx}}
{{Mydriatics and cycloplegics}}
{{Receptor agonists and antagonists}}

[[Category:Anticholinergics]]
[[Category:Drugs]]

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