anticholinergic

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In medicine, anticholinergic refers to (side) effects that result from the inhibition of the neurotransmitter acetylcholine . Acetylcholine is an important neurotransmitter that plays a role both in many central nerve nuclei in the brain and in parts of the peripheral nervous system, for example the parasympathetic nervous system . In a somewhat simplified manner, the parasympathetic nervous system is the antagonist of the sympathetic nervous system , which is often referred to as the stress system. Often both systems supply the same organ and act in opposite directions, for example the sympathetic nervous system increases the heart rate and the parasympathetic nervous system lowers it. Practically all internal organs are sympathetically as well as parasympathetically innervated: heart , bronchi , blood vessels , intestines , bladder , sweat glands , but also parts of the sensory organs such as the iris . Substances or drugs that inhibit the action of acetylcholine, i.e. have an anticholinergic effect, therefore lead to a characteristic symptom complex ( anticholinergic syndrome ):

In addition, there may also be central nervous effects:

The classic anticholinergic is the alkaloid atropine , obtained from the deadly nightshade ( Atropa belladonna L.) , whose pupil-expanding effect was used for cosmetic purposes centuries ago. Similar active ingredients are found in thorn apple and henbane . Poisoning occurs occasionally in children who have eaten such plants, but also in drug experiments ( datura / thorn apple ).

Many drugs have an anticholinergic effect, sometimes desirable, sometimes as a side effect. In emergency medicine, atropine is often used for hypotension and bradycardia . Other drugs are designed to specifically restore the neurotransmitter balance in Parkinson's disease by inhibiting central cholinergic synapses. With antidepressants , especially the classic tricyclic ones , anticholinergic effects occur regularly as a side effect.

As an antidote to cholinesterase inhibitors are used. Cholinesterases are enzymes that break down acetylcholine in the synaptic cleft. By inhibiting them, the local concentration of acetylcholine increases and the anticholinergic effect is reduced. Otherwise, the therapy is symptomatic in the case of pronounced anticholinergic syndrome: cooling, darkening, oxygen, possibly ventilation in the case of insufficient breathing, benzodiazepines in the case of cramps.

Individual evidence

  1. ↑ J. Klingelhöfer: Clinical Guide Neurology. Urban & FischerVerlag, 2009, ISBN 978-3-437-23142-1 , p. 249, (books.google.de) .