Doctors may recommend dicyclomine, sold under the brand name Bentyl, to treat irritable bowel syndrome (IBS) because it can effectively relieve symptoms such as abdominal pain and spasms.

IBS is a chronic condition of the digestive system that causes constipation, bloating, and diarrhea.

It is one of the most common disorders affecting the gastrointestinal tract.

According to the American College of Gastroenterology, many treatment options for IBS improve individual symptoms, but only a few improve overall symptoms.

This article provides an overview of Bentyl in IBS treatment, including its effectiveness, the recommended dosages, and other treatment options.

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Bentyl is a brand name for the medication dicyclomine. The Food and Drug Administration (FDA) first approved its use in the United States in 1996 to treat peptic ulcer disease. Now, doctors more commonly prescribe it to treat IBS.

It acts as an anticholinergic, blocking the action of acetylcholine, a neurotransmitter that transfers signals among cells in the body.

Additionally, as an antispasmodic, it can relax the smooth muscles of the intestines and inhibit the involuntary muscle movement of the digestive system that IBS can cause.

Bentyl is available in the following forms:

  • capsule
  • tablet
  • syrup
  • injection

A person should speak with a doctor before using Bentyl.

People with IBS often experience cramps and irregular bowel movements due to painful contractions of the gut muscles. Bentyl can help relieve involuntary muscle spasms and other accompanying symptoms of IBS.

A doctor may recommend Bentyl as a short- or long-term treatment option for IBS. Many people experience relief within hours of taking the medication.

A 2015 review indicates that dicyclomine can provide relief of intestinal spasms and accompanying pain for people with IBS.

What symptoms Bentyl improves

Although doctors frequently prescribe Bentyl to treat IBS, there is limited research on its effectiveness.

In a 1981 study, researchers administered 40 milligrams (mg) of hydrochloride four times per day. They found that Bentyl was superior to a placebo in improving the following symptoms:

  • abdominal pain
  • gastrointestinal tenderness
  • bowel function
  • overall IBS symptoms

However, most participants who took dicyclomine instead of a placebo had some side effects, including:

Other common side effects of Bentyl, which affect more than 5% of people who take it, include:

  • nausea
  • drowsiness
  • nervousness
  • body weakness

Additional potential side effects include:

If a person taking Bentyl has serious side effects, they should consult a doctor immediately.

A person can take Bentyl by mouth as directed by a doctor, usually four times per day. They can take it either with food or on an empty stomach.

To reduce the risk of side effects, a doctor will start a person on a low dose and gradually increase the dose while monitoring their symptoms.


A doctor can start a person on 20 mg of Bentyl four times per day. After a week of treatment with the starting dose, the doctor may increase the dose to 40 mg four times per day.

The doctor will adjust an individual’s dosage to meet their needs. However, the doctor may not increase a person’s dose if they have side effects.

For people who cannot take medication orally, health experts recommend intramuscular injections of 10–20 mg four times daily.

Bentyl can affect the activity of some medications, including:

  • Antiglaucoma agents: Anticholinergics may cause adverse reactions with antiglaucoma agents and increase pressure inside the eyes. Examples of antiglaucoma eye drops include latanoprost and timolol.
  • Antacids: Doctors do not recommend taking antacids — medications for heartburn — with Bentyl. Antacids interfere with the absorption of anticholinergic agents.
  • Other anticholinergic agents: Other anticholinergic agents may amplify Bentyl’s side effects or specific actions. Some examples of anticholinergic agents are the over-the-counter medication Benadryl (diphenhydramine) and the prescription medications solifenacin (Vesicare) and oxybutynin (Ditropan XL).

Health experts do not recommend Bentyl for infants younger than 6 months of age, people who are nursing, or people with the following conditions:

There is currently no cure for IBS, but other treatment options exist besides Bentyl.

If someone has IBS, they should discuss treatment options with a doctor to find the best way to reduce their symptoms. Other treatment options to manage IBS include:

  • Diet: “FODMAPs” stands for “fermentable oligo-, di-, and monosaccharides and polyols.” FODMAPs can trigger digestive symptoms such as gas, bloating, stomach pain, and altered bowel habits in people with IBS. Research suggests that a low FODMAP diet can reduce gastrointestinal symptoms in IBS.
  • Other IBS medications: A doctor may recommend some FDA-approved medications for IBS, such as:
    • Lotronex
    • Viberzi
    • Amitiza
    • Xifaxan
    • Linzess
  • Psychotherapy: Research from 2015 suggests that hypnotherapy and cognitive behavioral therapy may reduce symptoms of IBS flares. They can equip people with strategies to better cope with IBS.
  • Fiber supplements: Fiber supplements such as psyllium (Metamucil) can help people manage IBS symptoms.
  • Antidiarrheal medication: Based on limited evidence from small studies, loperamide (Imodium), an antidiarrheal agent, may help improve stool consistency, pain, and frequency.
  • Antidepressants: Off-label use of tricyclic antidepressants such as desipramine can relieve IBS symptoms.
  • Anticonvulsants: Pregabalin may be beneficial for IBS symptoms such as bloating and diarrhea.
  • Herbal remedies: Mentha piperita (peppermint) may help manage abdominal pain from IBS.

Bentyl is a drug that blocks the activity of the neurotransmitter acetylcholine. It may help reduce painful muscle spasms in the gut that IBS can cause. If someone has IBS, they can speak with a doctor about treatment options that might be right for them.

Following a doctor’s recommendations, such as taking medications, avoiding trigger foods, and following a low FODMAP diet, can offer significant benefits.

However, Bentyl can cause side effects such as hallucinations and drowsiness. People should inform a doctor if they notice any adverse effects after taking this medication.