Dicyclomine: uses, dosing, side effects & brands

Dicyclomine Hydrochloride is an anticholinergic used to treat Irritable Bowel Syndrome.

The FDA classifies dicyclomine as an anticholinergic. Anticholinergic drugs block acetylcholine, the chemical messenger of the body's "rest and digest" nervous system, by occupying its muscarinic receptors. This eases muscle spasms, dries up secretions, relaxes the bladder and airways, and speeds the heart, depending on the tissue. If you are checking whether it is safe to combine with something else, the class is what matters — two drugs from the same class usually should not be stacked.

It depends on the medicine. We check it against the FDA labels rather than guessing: our interaction checker searches each drug's own label for the other and quotes what it says, naming the section it came from. Run dicyclomine against whatever else you take — and remember that a label not naming a drug is not the same as that combination being safe.

We track 3 dicyclomine-containing products in the U.S.: Bentyl, Bentyl Preservative Free and Dicyclomine Hydrochloride. They are the same active ingredient; they differ in form, manufacturer, price and FDA recall record.

Across the brands we track, dicyclomine is currently marketed as capsule, tablet, syrup, injectable and solution, per the FDA's National Drug Code Directory. Each form is dosed differently — follow the label for the exact product you were prescribed.

Yes. Our catalog lists 1 generic dicyclomine product alongside the brand versions. A generic has the same active ingredient and must meet the FDA's bioequivalence standard; it usually costs less. Ask your pharmacist which one your plan covers.

The FDA's Enforcement database lists 1 recall record whose product description mentions dicyclomine. The most recent: Dicyclomine Hydrochloride Capsules (Jul 23, 2026). A recall applies to specific lots, not to the drug as a whole — check the record for the affected lot numbers.

Very common at full dose. In the FDA label's controlled IBS trials at 40 mg four times a day (160 mg daily), 61% of patients reported side effects, and 9% stopped the drug because of them versus 2% on placebo. The individual rates: dizziness 40% (placebo 5%), dry mouth 33% (placebo 5%), blurred vision 27% (placebo 2%), nausea 14% (placebo 6%), somnolence 9%, weakness 7%, and nervousness 6%. Dizziness, not dry mouth, is the single most frequent one. These are anticholinergic effects — the same action that relaxes gut spasm also dries secretions, relaxes the eye's focusing muscle, and slows the bladder.

Often you can keep the benefit at a lower dose. In the label's trials, among patients who had side effects, 41% found they resolved or were tolerated at 160 mg daily without any dose reduction, and 46% needed a reduction from 160 mg daily to an average of about 90 mg daily, after which they still had a favorable clinical response with the side effects gone or tolerable. That is why the label starts adults at 20 mg four times a day for the first week and only then escalates to 40 mg four times a day unless side effects limit it. The label also sets an exit rule: if efficacy is not achieved within 2 weeks, or if side effects force doses below 80 mg a day, the drug should be discontinued. Blurred vision and drowsiness make driving unsafe until you know how it affects you.

Heat stroke is the one people never see coming. Because dicyclomine reduces sweating, the FDA label warns that heat prostration — fever and heat stroke — can occur in high environmental temperatures, and instructs that the drug be discontinued and supportive measures started if it happens. If you are working outdoors, exercising in summer, or using a sauna and you stop sweating, feel confused, and your skin is hot and dry, that is a 911 situation. Also seek urgent care for: confusion, disorientation, hallucinations, or delirium, which the label reports in individuals sensitive to anticholinergic drugs and which usually resolve 12 to 24 hours after stopping; inability to urinate; a fast or pounding heartbeat; severe abdominal distension with vomiting; or eye pain with halos around lights, which can signal acute glaucoma.

The FDA label contraindicates it in infants under 6 months, in nursing mothers, and in anyone with glaucoma, myasthenia gravis, obstructive uropathy, obstructive disease of the GI tract, severe ulcerative colitis, reflux esophagitis, or unstable cardiovascular status in acute hemorrhage. Three of those are worth explaining. Infants: the label reports published cases in which giving dicyclomine syrup to infants was followed by serious respiratory symptoms including apnea and asphyxia, seizures, syncope, muscular hypotonia, coma, and death — no causal relationship has been established, but the label directs that parents and caregivers be specifically counseled never to give it to a baby under 6 months. Reflux esophagitis: dicyclomine relaxes the same sphincter that keeps acid down, so it can make GERD worse. Severe ulcerative colitis: large doses can suppress intestinal motility enough to produce a paralytic ileus and can precipitate or aggravate toxic megacolon. The label also flags that diarrhea in someone with an ileostomy or colostomy may be an early sign of incomplete intestinal obstruction, where treating with dicyclomine would be inappropriate and possibly harmful. Older adults are told to use caution — they are more susceptible to every effect on this list.

Check first, because the effects stack. The label warns that dicyclomine may increase the actions or side effects of other anticholinergic drugs. Anything else with anticholinergic activity — diphenhydramine and other sedating antihistamines, tricyclic antidepressants, oxybutynin and bladder drugs, some Parkinson's medicines, promethazine — adds to the same dry mouth, blurred vision, constipation, urinary retention, and confusion burden, and the combined load is what tips older adults into delirium. The label also notes that anticholinergics can affect the gastrointestinal absorption of other drugs, and that antacids interfere with the absorption of dicyclomine itself. Bring your full list, including over-the-counter sleep aids and allergy products, to your pharmacist.