Dicyclomine is a drug that is used for treating irritable bowel syndrome IBS. Dicyclomine is in a class of drugs called anticholinergics. Anticholinergic drugs block the effects of acetylcholine the chemical transmitter that nerves release in order to cause muscles to contract. They prevent contraction of the muscles by blocking the acetylcholine receptors on the muscle cells. Anticholinergic drugs also have a direct relaxing effect on muscle. Dicyclomine is used to reduce contraction of the muscles in the intestines. Dicyclomine was approved by the FDA in 1950.

The recommended starting oral dose of dicyclomine is 20 mg given 4 times daily. The dose can be increased to 40 mg 4 times daily. The recommended intramuscular injection is 20 mg 4 times daily.

Side effects include dry mouth blurred vision confusion agitation increased heart rate heart palpitations constipation difficulty urinating and occasionally seizures can occur. Other potential side effects include changes in taste perception difficulty swallowing headache nervousness drowsiness weakness dizziness impotence flushing difficulty falling asleep nausea vomiting rash bloating and difficulty breathing.

Excessive anticholinergic effects may occur when dicyclomine is combined with other drugs with anticholinergic effects such as clemastine Tavist diphenhydramine Benadryl promethazine Phenergan thioridazine Mellaril triflupromazine Stelazine amitriptyline Elavil amoxapine Asendin clomipramine Anafranil protriptyline Vivactil clozapine Clozaril cyclobenzaprine Flexeril disopyramide Norpace. The combined effects of these drugs can lead to a greater incidence of dry mouth blurred vision confusion agitation increased heart rate palpitations constipation urinary retention difficulty urinating. Narcotics e.g. oxycodone Percocet Percodan hydrocodone Vicodin can interact with dicyclomine and result in greater depression of the muscles of the bowel and bladder resulting in greater constipation and difficulty urinating than may be seen with dicyclomine alone.

Dicyclomine adds to the sedating effects of alcohol and other drugs that cause sleepiness such as the benzodiazepine class of anti-anxiety drugs e.g. Valium Ativan Klonopin Xanax the narcotic class of pain medications and its derivatives e.g. Percocet Vicodin Dilaudid Codeine Darvon the tricyclic class of antidepressants e.g. Elavil Tofranil Norpramin and certain antihypertensive medications e.g. Catapres Inderal.

Dicyclomine can reverse the muscle activity-promoting effects of cisapride Propulsid or metoclopramide Reglan. Conversely these latter two drugs can reverse the effects of dicyclomine.

Antacids and absorbent anti-diarrheals e.g. Kaopectate can decrease the absorption of dicyclomine. Therefore doses of antacids or absorbent anti-diarrheals should be separated by at least 2 hours from doses of dicyclomine.

PREGNANCY: There are no adequate studies of the effect of dicyclomine in pregnant women at recommended doses 80-160 mg/day. Observation of women who received dicyclomine up to 40 mg/day containing products during the first trimester of pregnancy did not reveal any increased risk of harm to the fetus.

Dicyclomine is used in the treatment of irritable bowel syndrome.

Capsules and tablets should be stored at room temperature between 15° 59°F and 30°C 86°F.