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A racemic mixture of d- and l-hyoscyamine, alkaloids obtained from the leaves and roots of Atropa belladonna; an anticholinergic, with diverse effects (tachycardia, mydriasis, cycloplegia, constipation, urinary retention, antisudorific) attributable to reversible competitive blockade of acetylcholine at muscarinic type cholinergic receptors; used in the treatment of poisoning with organophosphate insecticides or nerve gases. The (–) form is by far the more active. SYN: dl-hyoscyamine, tropine tropate.
- a. methonitrate the methylnitrate of a., with the same actions and uses as a., but less lipid-soluble (due to the presence of a quaternary nitrogen atom that limits penetration of the blood-brain barrier) and hence with fewer central nervous system effects; a quaternary compound.
- a. methylbromide SYN: methylatropine bromide.
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at·ro·pine 'a-trə-.pēn n a racemic mixture of hyoscyamine usu. obtained from belladonna and related plants of the family Solanaceae and used esp. in the form of its hydrated sulfate (C17H23NO3)2·H2SO4·H2O for its anticholinergic effects (as relief of smooth muscle spasms or dilation of the pupil of the eye)
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n.
an anticholinergic drug that occurs in deadly nightshade (see belladonna). Atropine relaxes smooth muscle and is used to treat biliary colic and renal colic. It also reduces secretions of the bronchial tubes, salivary glands, stomach, and intestines and is used before general anaesthesia and to relieve peptic ulcers. It is also used as a mydriatic. Atropine is administered by mouth, injection, or as eye drops; common side-effects include dryness of the throat, thirst, and impaired vision. Trade name: Minims Atropine.
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at·ro·pine (atґro-pēn) [USP] an alkaloid derived from species of belladonna, hyoscyamus, or stramonium, or produced synthetically. It is an anticholinergic and antimuscarinic, used as an antispasmodic to relax smooth muscles and to increase and regulate the heart rate by blocking the vagus nerve. It also serves as an antidote for various toxic and anticholinesterase agents and as an antisecretory, mydriatic, and cycloplegic. Ingestion of excessive amounts causes atropinism.Medical dictionary. 2011.