Dicyclomine is an anticholinergic medication most frequently used to treat irritable bowel syndrome (IBS). The drug works by preventing the contraction of the muscles of the bowels to prevent frequent bowel movements. Most patients who are taking dicyclomine will receive four 20 milligram (mg) doses per day, but this can be increased if necessary. Common side effects of the drug include increased heart rate, dry mouth, difficulty urinating, and headache. More rare side effects include nervousness and difficulty sleeping, breathing, or swallowing.
Anticholinergic medicines such as dicyclomine prevent muscles from contracting by preventing the action of acetylcholine. This is a chemical transmitter which relays information to the muscles and causes them to contract. Each muscle cell has a specialized receptor for the receipt of acetylcholine. Dicyclomine and similar medicines work by blocking the receptors on the surface of the muscle cells and therefore preventing acetylcholine from working. The drug has been widely used since the 1950s to relax intestinal muscles in patients suffering from conditions such as IBS.
IBS is a common bowel condition, classified as a “functional” issue, which can be treated using dicyclomine. The condition affects around 15 percent of the population, and is amongst the most common bowel problems. It is a “functional” condition because either the nerves or the muscles which control the organs are not functioning correctly. This can cause problems such as bloating, nausea, vomiting, and diarrhea. Increased flatulence can also be a result of irritable bowel syndrome.
The most common side effects associated with the use of dicyclomine include agitation, confusion, and seizures. The drug can also cause constipation and difficulty urinating because it prevents muscles from contracting as normal. These common side effects are only cause for concern if they are particularly persistent or severe. Rare side effects such as weakness, impotence, rash, and changes in taste are more likely to be serious. Hallucinations, blurred vision, and dilated pupils can occur if a patient has overdosed on dicyclomine.
Patients taking the oral pill form of dicyclomine are usually given 20 mg doses four times per day. If the drug is not effective at this dosage, doctors can opt to increase the dosage to 40 mg four times per day. Intramuscular injections — liquid solutions of the drug injected into the muscle — usually consist of four 20 mg doses per day. Patients are recommended to take the drug at the same times each day to decrease the likelihood of a missed dose.