atropine eye drops

Atropine occurs naturally and is extracted from belladonna alkaloids contained in plants. Atropine blocks the action of acetylcholine, a neurotransmitter that causes the contraction of two types of muscle, smooth and cardiac muscles. It also has other neurological effects.

Ophthalmic atropine is used during eye examinations to dilate the pupil. Atropine is also used to weaken the contraction of the muscles within the eyes, both the muscles that operate the iris and the lens. Paralysis of the lens, called cycloplegia, results in the loss of the ability to focus vision. Paralysis of the iris (mydriasis) prevents the iris from adjusting to the brightness of incoming light and affects the ability to see clearly.

In clinical studies, use of a single topical administration of atropine 1% ophthalmic solution (eye drops) resulted in maximal mydriasis (pupil dilation or widening) in approximately 40 minutes and maximal cycloplegia in approximately 60 to 90 minutes. In most cases, full recovery occurred in approximately one week but can take a couple of weeks. The FDA approved atropine in 1938.

The most common side effects reported include

• eye pain,
• stinging on administration,
• blurred vision,
• sensitivity to light,
• decreased tear production,
• eyelid swelling, and
• increased heart rate and blood pressure if the atropine is absorbed from the eye.

• For inducing mydriasis (pupil dilation) or cycloplegia in adults: Instill 1-2 drops of 1% ophthalmic solution in eye 1 hour before procedure.
• For the treatment of inflammatory conditions of the eye (iritis or uveitis) in adults: Instill 1-2 drops of 1% solution in eye up to 4 times per day.

Use of atropine with monoamine oxidase inhibitors (MAOI) is not recommended due to the risk of causing severely elevated blood pressure (hypertensive crisis). Examples of MAO inhibitors include

• linezolid (Zyvox),
• methylene blue,
• phenelzine (Nardil),
• procarbazine (Matulane),
• rasagiline (Azilect),
• selegiline (Eldepryl, Zelapar, Carbex),
• tranylcypromine (Parnate) and others.

Patients should ask their doctor or pharmacist before using atropine eye products if they are taking certain drugs such as

• antiarrhythmic drugs, for example, quinidine, procainamide (Procanbid), antihistamines such as meclizine (Antivert) or diphenhydramine (Benadryl),
• antispasmodics such as dicyclomine (Bentyl),
• certain medications used to treat Parkinson's disease such as benztropine (Cogentin) or trihexyphenidyl (Artane), and
• antidepressants, for example amitriptyline (Endep, Elavil).

There are no adequate and well-controlled studies of atropine sulfate in pregnant women

Small amounts of atropine were detected in human milk following administration of injectable atropine. Ophthalmic preparations of atropine are compatible with breastfeeding.

What preparations of atropine are available?

Ophthalmic solution: 1%

How should I keep atropine stored?

Atropine ophthalmic solution can be stored in the refrigerator or at room temperature away from heat and light.