What Is Carbachol?

Carbachol is a drug used to treat urine retention by activating acetylcholine, a natural chemical in the human body that prompts the bladder to contract and release urine. Patients unable to start a stream of urine, or those whose bladders fail to completely empty, might be prescribed this medication. Another form of the drug, defined as carbachol ophthalmic, is used to ease pressure in the eye caused by glaucoma.

Delayed urination or urination hesitancy commonly occurs in older men who suffer from prostate problems. An enlarged prostate might cause retention of urine, leading to a weak flow of urine that dribbles instead of flowing freely. Some patients experience trouble starting a urine flow. The condition could also affect younger men and women, and may start slowly without obvious symptoms. Delayed urination might progress to complete retention marked by a distended and painful bladder.

Carbachol might help the disorder by creating spasms in the bladder muscle to permit urination. In addition to prostate conditions, the drug might be prescribed for patients with shy bladders, meaning they cannot urinate in public or when other people are nearby. Some unrelated medications, such as antihistamines taken to dry up excess mucus from a cold or flu, might also cause patients to hold urine.

Other medications that might hinder bladder contractions include those prescribed for incontinence. These drugs might be used by patients who feel a sudden, urgent need to urinate that might lead to leakage. Some people lose urine when they cough or sneeze. Patients taking these medications should inform their doctors before using carbachol for urinary tract disorders.

When used in ophthalmology, carbachol drops in the eye relieve pressure by decreasing the level of fluid. These drops might also shrink the size of pupils, making them less responsive at night or in dark areas. This side effect might affect night driving or activities in poorly lit rooms.

A rare side effect involves retina detachment, which could cause blind spots in vision or total blindness. Symptoms typically are first seen as floating objects, which should be reported to the ophthalmologist. Patients with previous surgery for cataracts, and those who are nearsighted, face higher risks of complications using carbachol drops.

Carbachol is not recommended for patients with epilepsy, Parkinson’s disease, asthma, or ulcers. Pregnant women or breastfeeding mothers should also avoid the drug because the potential for adverse reactions in a fetus or nursing baby is not known. Reactions might also occur in patients with low blood pressure or overactive thyroids.