n. an anticholinergic drug derived from plants, particularly from belladonna (see also belladonna alkaloids). It is also produced synthetically. Its effects include increased heart rate, increased rate of breathing, relaxation of smooth muscles, and reduction of bodily secretions (e.g., saliva). It may be used to treat bradycardia (slowing of the heart rate), or as an adjunct to anesthesia. However, it is most commonly employed in eye examinations to dilate the pupil before examination. Atropine is closely related, chemically and pharmacologically, to scopolamine, another substance.
ATROPINE: "A person's pupil was dilated with atropine prior to the eye examination. "