anticholinergic

inhibiting the action of ACETYLCHOLINE , the neurotransmitter that conveys information in the parasympathetic nervous system. Anticholinergic drugs block the effects of certain (muscarinic) receptors; hence they are also called antimuscarinic drugs. The actions of these drugs include relaxation of smooth muscle, decreased secretion of saliva, sweat, and digestive juices, and dilation of the pupil of the eye. ATROPINE and similar drugs have these effects; they are used in the treatment of gut spasms (e.g. PROPANTHELINE ) and of parkinsonism (e.g. TRIHEXYPHENIDYL , BENZATROPINE ), as bronchodilators (e.g. IPRATROPIUM , THEOPHYLLINE ), and as MYDRIATIC . Characteristic side-effects include dry mouth, thirst, blurred vision, dry skin, increased heart rate, and difficulty in urination.