Atropine is a medicine derived from the deadly nightshade plant, which has a muscle relaxant and anesthetic effect. It makes the pupils of the eye enlarge, so it is sometimes used as an eye drop for ophthalmic examinations. Atropine eye drops can also ease the pain of an inflamed eye. Side effects are generally mild, but an overdose can have severe consequences.
The deadly nightshade plant, also known as belladonna, is poisonous as it contains many alkaloid chemicals that have a physiological effect on humans. Atropine, found in the leaves and roots of the plant, is one of these alkaloids and has been used in medicine for centuries. According to the University of Iowa in the United States, atropine eye drops were historically used by women in Italy to dilate their pupils and make their eyes brighter.
An ophthalmologist can use atropine eye drops in much the same way. The atropine blocks the transmission of a nervous system signal called acetylcholine to the muscarinic receptor, which usually controls muscle. The result is a relaxing of smooth muscle in the eye.
The pupil of the eye is controlled at a certain width to let in an optimum level of light by these muscles. Atropine eye drops relax these muscles and allow the pupil to open wider. This allows the ophthalmologist to see the inside of the eye more clearly. The drops may also be used to relax pupillary muscles in children who are undergoing eye surgery.
A course of treatment with atropine for eye inflammation generally involves using the eye drops twice to four times a day. A patient who has glaucoma or who is allergic to belladonna products should consult his or her doctor prior to using the drops. Atropine can also pass the placental barrier and affect breast milk, so the drops are not suitable for pregnant or breast-feeding women.
Atropine eye drops can cause both mild and severe side effects. Due to the pupil-widening effect, the eye can be unusually sensitive to light. Eye irritation, blurred vision, and a dry mouth are also possible. Severe side effects include confusion, irregular pulse, and problems urinating.
An overdose of atropine can be fatal as it affects the circulatory system and the nervous system. Brand names of atropine eye drops include Atropine Care® 1%, Ocu-Tropine®, and Atropisol®. Atropine eye treatments can also be in an ointment form.