In the U.S.—

In Canada—

Another commonly used name is carbamylcholine.

• Antiglaucoma agent, ophthalmic
• Antihypertensive agent, ocular, postsurgical
• Miotic

Carbachol (KAR-ba-kole ) is used in the eye to treat glaucoma. Sometimes it is also used in eye surgery.

This medicine is available only with your doctor's prescription, in the following dosage forms:

Ophthalmic
• Intraocular solution (U.S. and Canada)
• Ophthalmic solution (eye drops) (U.S. and Canada)

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For carbachol, the following should be considered:

Allergies—Tell your doctor if you have ever had any unusual or allergic reaction to carbachol. Also tell your health care professional if you are allergic to any other substances, such as preservatives.

Pregnancy—Studies on effects in pregnancy have not been done in either humans or animals. However, carbachol may be absorbed into the body.

Breast-feeding—Carbachol may be absorbed into the mother's body. However, it is not known whether carbachol passes into breast milk. Although most medicines pass into breast milk in small amounts, many of them may be used safely while breast-feeding. Mothers who are using this medicine and who wish to breast-feed should discuss this with their doctor.

Children—Although there is no specific information comparing use of carbachol in children with use in other age groups, this medicine is not expected to cause different side effects or problems in children than it does in adults.

Older adults—Many medicines have not been studied specifically in older people. Therefore, it may not be known whether they work exactly the same way they do in younger adults. Although there is no specific information comparing use of carbachol in the elderly with use in other age groups, this medicine is not expected to cause different side effects or problems in older people than it does in younger adults.

Other medicines—Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. Tell your health care professional if you are using any other prescription or nonprescription (over-the-counter [OTC]) medicine.

• Asthma or
• Eye problems (other) or
• Heart disease or
• Overactive thyroid or
• Parkinson's disease or
• Stomach ulcer or other stomach problems or
• Urinary tract blockage—Carbachol may make the condition worse

Use this medicine only as directed. Do not use more of it and do not use it more often than your doctor ordered. To do so may increase the chance of too much medicine being absorbed into the body and the chance of side effects.

To use:

• First, wash your hands. Tilt the head back and, pressing your finger gently on the skin just beneath the lower eyelid, pull the lower eyelid away from the eye to make a space. Drop the medicine into this space. Let go of the eyelid and gently close the eyes. Do not blink. Keep the eyes closed and apply pressure to the inner corner of the eye with your finger for 1 or 2 minutes to allow the medicine to be absorbed by the eye.
• Immediately after using the eye drops, wash your hands to remove any medicine that may be on them.
• To keep the medicine as germ-free as possible, do not touch the applicator tip to any surface (including the eye). Also, keep the container tightly closed.

Dosing—

The dose of carbachol will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of carbachol. If your dose is different, do not change it unless your doctor tells you to do so.

• For glaucoma:
  • For ophthalmic solution (eye drops) dosage form:
    • Adults and children—Use one drop in the eye one to three times a day.
• For use during surgery:
  • For intraocular solution dosage form:
    • Adults and children—Up to 0.5 milliliter (mL), used in the eye during surgery.

Missed dose—

If you miss a dose of this medicine, apply it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Storage—

To store this medicine:

• Keep out of the reach of children.
• Store away from heat and direct light.
• Keep the medicine from freezing.
• Do not keep outdated medicine or medicine no longer needed. Be sure that any discarded medicine is out of the reach of children.

Your doctor should check your eye pressure at regular visits.

After you apply this medicine to your eyes, your pupils may become unusually small. This may cause you to see less well at night or in dim light. Be especially careful if you drive, use machines, or do anything else at night or in dim light that could be dangerous if you are not able to see well.

Also, for a short time after you apply this medicine, your vision may be blurred or there may be a change in your near or distance vision. Make sure your vision is clear before you drive, use machines, or do anything else that could be dangerous if you are not able to see well.

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• Rare
  • Veil or curtain appearing across part of vision 
  
  

• Symptoms of too much medicine being absorbed into the body
  • Diarrhea, stomach cramps or pain, or vomiting;  fainting;  flushing or redness of face;  frequent urge to urinate;  increased sweating;  irregular heartbeat;  shortness of breath, wheezing, or tightness in chest;  unusual tiredness or weakness;  watering of mouth  
  
  

Other side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. However, check with your doctor if any of the following side effects continue or are bothersome:

• More common
  • Blurred vision or change in near or distance vision;  eye pain;  stinging or burning of the eye 
  
  

• Less common
  • Headache;  irritation or redness of eyes ;  twitching of eyelids 
  
  

Other side effects not listed above may also occur in some patients. If you notice any other effects, check with your doctor.