From the Guidelines
Bentyl (dicyclomine) works by relaxing smooth muscles in the digestive tract to relieve symptoms of irritable bowel syndrome (IBS) and similar conditions, as an anticholinergic medication that blocks the action of acetylcholine, a neurotransmitter that stimulates muscle contractions in the intestines. This mechanism of action is supported by a study published in 2021 in the journal Gut, which discusses the use of antispasmodics, including dicyclomine, in the management of IBS 1. According to this study, antispasmodics can be divided into antimuscarinics and smooth muscle relaxants, and they work by reducing intestinal motility and ameliorating gastrointestinal spasm and dysmotility.
The study found that antispasmodics, including dicyclomine, can significantly reduce global symptoms and abdominal pain in patients with IBS, with a relative risk of 0.65 (95% CI 0.56 to 0.76) 1. Another study published in 2000 in the same journal also supports the use of antispasmodics, including dicyclomine, in the management of IBS, and found that they can provide significant additional benefit over placebo in reducing abdominal pain and global symptoms 1.
In terms of dosage and administration, the typical adult dosage of Bentyl is 20-40 mg taken orally 4 times daily, though treatment usually begins with lower doses that are gradually increased. Patients should take Bentyl 30-60 minutes before meals for optimal effect. Side effects may include dry mouth, blurred vision, dizziness, and constipation due to its anticholinergic properties. Bentyl should be used cautiously in elderly patients and is contraindicated in certain conditions like glaucoma, urinary retention, and severe ulcerative colitis.
Some key points to consider when using Bentyl include:
- It is an anticholinergic medication that blocks the action of acetylcholine
- It relaxes smooth muscles in the digestive tract to relieve symptoms of IBS and similar conditions
- It can significantly reduce global symptoms and abdominal pain in patients with IBS
- It should be used cautiously in elderly patients and is contraindicated in certain conditions
- It can cause side effects such as dry mouth, blurred vision, dizziness, and constipation
Overall, Bentyl is a useful medication for the management of IBS and similar conditions, and its mechanism of action and efficacy are supported by recent and high-quality studies, such as the one published in 2021 in the journal Gut 1.
From the FDA Drug Label
Dicyclomine relieves smooth muscle spasm of the gastrointestinal tract Animal studies indicate that this action is achieved via a dual mechanism: a specific anticholinergic effect (antimuscarinic) at the acetylcholine-receptor sites with approximately 1/8 the milligram potency of atropine ( in vitro, guinea pig ileum); and a direct effect upon smooth muscle (musculotropic) as evidenced by dicyclomine’s antagonism of bradykinin- and histamine-induced spasms of the isolated guinea pig ileum.
Bentyl (dicyclomine) works by relieving smooth muscle spasm of the gastrointestinal tract through a dual mechanism:
- Anticholinergic effect (antimuscarinic) at the acetylcholine-receptor sites
- Direct effect upon smooth muscle (musculotropic) 2
From the Research
Mechanism of Action
- Bentyl (dicyclomine) works by relaxing the muscles in the stomach and intestines, thereby relieving abdominal pain and discomfort associated with irritable bowel syndrome (IBS) 3.
- It is an anticholinergic agent that inhibits the action of acetylcholine, a neurotransmitter that stimulates muscle contractions in the gastrointestinal tract 4.
Efficacy
- Studies have shown that dicyclomine is effective in improving the overall condition of patients with IBS, decreasing abdominal pain, and improving bowel habits 3, 5.
- However, another study suggests that dicyclomine and hyoscyamine, another myorelaxant, have not been proven effective in reducing abdominal pain in patients with IBS 6.
Side Effects
- The majority of adverse effects reported with dicyclomine are related to its anticholinergic activity, such as dry mouth, dizziness, and blurred vision 3.
- Other studies have also reported similar side effects, highlighting the need for careful consideration of the benefits and risks of using dicyclomine in patients with IBS 4, 5.