An anticholinergic drug derived from belladonna. Atropine is used to dilate the pupil in eye conditions
such as iritis (inflammation of the iris) and corneal ulcer. It is also used in children before eye examination. Atropine may be included in a premedication before general anaesthesia to reduce respiratory secretions and is also used as an emergency treatment for bradycardia (abnormally slow heartbeat). It is sometimes combined with an antidiarrhoeal drug to relieve abdominal cramps accompanying diarrhoea.
Adverse effects include dry mouth, blurred vision, retention of urine, and, in the elderly, confusion.
Atropine eyedrops are rarely given to adults because they cause disturbance of vision lasting 2–3 weeks and may precipitate acute glaucoma in susceptible people.
An alkaloid derived from Belladonna (Atropa belladonna) and related plants that blocks some cholinergic or parasympathetic functions. It has been used to stop the cramps of diarrhea and is still found in some OTC cold remedies, since it dries up secretions. The main current medical use is in eye drops used to dilate the pupil.
Atropine is the active principle of belladonna, the juice of the deadly nightshade. Because of its action in dilating the pupils, it was at one time used as a cosmetic to give the eyes a full, lustrous appearance. Atropine acts by antagonising the action of the PARASYMPATHETIC NERVOUS SYSTEM. It temporarily impairs vision by paralysing accommodative power (see ACCOMMODATION). It inhibits the action of some of the nerves in the AUTONOMIC NERVOUS SYSTEM. The drug relaxes smooth muscle. It has the e?ect of checking the activity of almost all the glands of the body, including the sweat glands of the SKIN and the SALIVARY GLANDS in the mouth. It relieves spasm by paralysing nerves in the muscle of the intestine, bile ducts, bladder, stomach, etc. It has the power, in moderate doses, of markedly increasing the rate of the heartbeat, though by very large doses the heart, along with all other muscles, is paralysed and stopped.
Uses In eye troubles, atropine drops are used to dilate the pupil for more thorough examination of the interior of the eye, or to draw the iris away from wounds and ulcers on the centre of the eye. They also soothe the pain caused by light falling on an in?amed eye, and are further used to paralyse the ciliary muscle and so prevent accommodative changes in the eye while the eye is being examined with the OPHTHALMOSCOPE. Given by injection, atropine is used before general ANAESTHESIA to reduce secretions in the bronchial tree. The drug can also be used to accelerate the heart rate in BRADYCARDIA as a result of coronary thrombosis.
n. an *antimuscarinic drug that occurs in deadly nightshade (see belladonna). Because it dilates the pupil and paralyses the ciliary muscle (see cycloplegia; mydriatic), atropine is used in eye examinations and the treatment of anterior *uveitis. It is also administered by injection to treat a slow heart rate (*bradycardia) associated with arrhythmias or, with *neostigmine, to reverse the action of muscle relaxants used during surgery. It is sometimes used to treat gut spasms and – rarely – for *premedication. Common side-effects include dryness of the throat, thirst, impaired vision, and increased heart rate.
Health Encyclopedia