anticholinergic drug
any pharmacological agent that blocks or otherwise interferes with the release of the neurotransmitter acetylcholine and thus disrupts the transmission of impulses along parasympathetic routes. Anticholinergic drugs act at acetylcholine receptors, with the majority of such drugs acting at muscarinic receptors and known as antimuscarinic drugs; the others act at nicotinic receptors and are known as antinicotinic drugs. In large doses, anticholinergic drugs may also interfere with actions of histamine, serotonin, and norepinephrine. Natural anticholinergic drugs include atropine and scopolamine. A variety of synthetic anticholinergic drugs are used to treat neurological disorders, many as antiparkinsonian drugs. They include benztropine, biperiden, procyclidine, and trihexyphenidyl, which are administered primarily to relieve the symptoms of muscular rigidity. Anticholinergic
drugs are often used in combinations to control specific symptoms. Tricyclic antidepressants and some conventional antipsychotics also have anticholinergic activity. Also called parasympatholytic drug.