Medically Reviewed on 8/5/2022

Generic Name: acetylcholine

Brand Name: Miochol E

Drug Class: Miotics, Direct-Acting

What is acetylcholine, and what is it used for?

Acetylcholine is a medication instilled into the eye during certain ocular surgeries to achieve rapid constriction (miosis) of the pupils for a short period.

Acetylcholine belongs to a class of medications known as direct-acting miotics which act directly on specific eye muscles to cause miosis. The miotic effect occurs immediately and lasts for approximately 10 minutes.

Acetylcholine is a natural chemical (neurotransmitter) that nerve endings in muscles secrete to stimulate muscle contraction. Acetylcholine used as medication mimics the activity of the natural neurotransmitter. Acetylcholine is instilled into the anterior chamber of the eye which makes the eye’s ciliary muscle and the sphincter muscle encircling the iris contract, resulting in miosis. Acetylcholine works by stimulating protein molecules known as cholinergic receptors on the eye muscle cells that induce contraction in response to acetylcholine.

Acetylcholine is approved by the FDA for achieving miosis of the iris in seconds after delivery of the lens in cataract surgery, in penetrating keratoplasty, iridectomy and other anterior segment surgeries where rapid miosis may be required.


  • Do not use acetylcholine in patients with hypersensitivity to any of the components in the acetylcholine formulation.
  • Open the pack under aseptic conditions. If package is damaged, discard the drug, do not gas sterilize.
  • Aqueous solutions of acetylcholine are unstable. Prepare solution immediately before use. Do not use the solution if it is not clear and colorless. Discard any solution that has not been used.
  • Instill the solution gently, forceful jet may rupture the hyaloid artery, cause vitreous loss, or injure/perforate the iris.
  • Rarely, systemic absorption can cause problems for patients with asthma, acute heart failure, gastrointestinal spasm, peptic ulcer disease, urinary tract obstruction, acute heart failure and hyperthyroidism.

What are the side effects of acetylcholine?

Common side effects of acetylcholine include:

Call your doctor immediately if you experience any of the following symptoms or serious side effects while using this drug:

This is not a complete list of all side effects or adverse reactions that may occur from the use of this drug. Call your doctor for medical advice about serious side effects or adverse reactions. You may also report side effects or health problems to the FDA at 1-800-FDA-1088.


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What are the dosages of acetylcholine?

Powder for Injection

  • 20 mg


Miosis During Ocular Surgery

  • 0.5-2 mL of 1% solution intraocular instillation during surgery
  • Miosis occurs promptly and persists for approximately 10 minutes


  • Reconstitute vial with 2 mL supplied diluent to obtain 1% solution; use immediately
  • Instill gently into anterior chamber of eye with suitable atraumatic cannula
  • May use 2% pilocarpine or 0.25% physostigmine topically immediately after surgery before application of dressing to maintain miosis
  • For cataract surgery, instill only after delivery of lens


  • Safety and efficacy not established


Overdose of acetylcholine can result in systemic absorption and may cause hypotension, bradycardia, breathing difficulties, flushing, and sweating. Overdose effects may be reversed with intravenous or intramuscular administration of atropine sulfate. Epinephrine may be used if there are cardiovascular or bronchoconstrictor effects.

What drugs interact with acetylcholine?

Inform your doctor of all medications you are currently taking, who can advise you on any possible drug interactions. Never begin taking, suddenly discontinue, or change the dosage of any medication without your doctor’s recommendation.

  • Acetylcholine has no known severe, serious, moderate or mild interactions with other drugs.

The drug interactions listed above are not all of the possible interactions or adverse effects. For more information on drug interactions, visit the RxList Drug Interaction Checker.

It is important to always tell your doctor, pharmacist, or health care provider of all prescription and over-the-counter medications you use, as well as the dosage for each, and keep a list of the information. Check with your doctor or health care provider if you have any questions about the medication.

Pregnancy and breastfeeding

  • There are no well-controlled studies on the safety of acetylcholine for ophthalmic surgery in pregnant women. Use only if benefits to the mother outweigh possible risks to the mother and fetus.
  • It is not known if acetylcholine is present in breast milk. Although instillation into the eye is unlikely to result in significant systemic absorption, use with caution in nursing mothers.


Acetylcholine is a medication instilled into the eye during certain ocular surgeries to achieve rapid constriction (miosis) of the pupils for a short period. Common side effects of acetylcholine include clouding of the cornea, corneal swelling (edema), corneal decompensation, flushing, low blood pressure (hypotension), slow heart rate (bradycardia), shortness of breath (dyspnea), and sweating (diaphoresis). Consult your doctor before taking acetylcholine if pregnant or breastfeeding.

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Report Problems to the Food and Drug Administration

You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.

Medically Reviewed on 8/5/2022