atropine

American  

[a-truh-peen, -pin] / ˈæ trəˌpin, -pɪn /

noun

Pharmacology.

1. a poisonous crystalline alkaloid, C 17 H 23 NO 3 , obtained from belladonna and other plants of the nightshade family, that prevents the response of various body structures to certain types of nerve stimulation: used chiefly to relieve spasms, to lessen secretions, and, topically, to dilate the pupil of the eye.

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atropine British  

/ ˈætrəˌpiːn, ˈætrəpɪn, -pɪn /

noun

1. a poisonous alkaloid obtained from deadly nightshade, having an inhibitory action on the autonomic nervous system. It is used medicinally in pre-anaesthetic medication, to speed a slow heart rate, and as an emergency first-aid counter to exposure to chemical warfare nerve agents. Formula: C 17 H 23 NO 3

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atropine Scientific  

/ ăt′rə-pēn′,-pĭn /

1. A poisonous, bitter, crystalline alkaloid derived from deadly nightshade and related plants. It is used as a drug to dilate the pupils of the eye and to inhibit muscle spasms. Chemical formula: C ₁₇ H ₂₃ NO ₃ .

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Etymology

Origin of atropine

1830–40; < New Latin Atrop ( a ) belladonna genus (< Greek átropos; see Atropos) + -ine ²

Example Sentences

Atropine eye drops are typically used to dilate the pupil before eye exams.

From The Wall Street Journal • Dec. 28, 2025

Atropine is one of the first treatments used to counteract those immediate effects.

From Reuters • Sep. 6, 2020

Atropine is the most common treatment for poisoning by a cholinesterase inhibitor.

From Washington Post • Aug. 24, 2020

Atropine goes in, to keep the heart working.

From The New Yorker • Jan. 27, 2014

“They are exactly opposite in effect. Atropine speeds the nervous system, rapid heartbeat and so forth. Amatoxins slow it down.”

From "The Secret History" by Donna Tartt