From the Guidelines
Dicyclomine is recommended for managing IBS symptoms, particularly for patients with diarrhea-predominant or mixed-type IBS, as it can reduce abdominal pain, cramping, and urgent bowel movements by relaxing the smooth muscles in the intestines. This medication, typically prescribed at 10-20 mg taken three to four times daily, works as an antispasmodic by blocking acetylcholine receptors that trigger intestinal contractions 1. According to the AGA clinical practice guideline on the pharmacological management of irritable bowel syndrome with diarrhea, antispasmodics, including dicyclomine, can provide adequate global relief of IBS symptoms and improve abdominal pain 1.
The mechanism of action of dicyclomine is based on reducing smooth muscle contraction and possibly visceral hypersensitivity, which can help alleviate IBS symptoms 1. The medication usually takes effect within 1-2 hours and may require 1-2 weeks of regular use before maximum benefit is achieved. Common side effects include dry mouth, blurred vision, dizziness, and constipation 1. Patients should take dicyclomine 30-60 minutes before meals for best results, avoid alcohol while using it, and stay hydrated.
It's essential to note that dicyclomine primarily addresses the pain and spasm components of IBS rather than addressing all symptoms, and it may not be suitable for IBS-constoration type patients as it can worsen constipation. The British Society of Gastroenterology guidelines on the management of irritable bowel syndrome also support the use of antispasmodics, including dicyclomine, for managing IBS symptoms 1. However, the overall certainty in evidence for the use of antispasmodics in IBS is low due to the serious risk of bias and publication bias 1.
Key points to consider when prescribing dicyclomine for IBS include:
- Starting with a low dose and titrating up as needed to minimize side effects
- Monitoring patients for common side effects such as dry mouth, blurred vision, and dizziness
- Avoiding use in patients with constinning IBS or those who may be prone to constinning
- Encouraging patients to take the medication 30-60 minutes before meals and to stay hydrated
- Considering alternative treatments if patients do not experience adequate relief of symptoms or if side effects are intolerable.
From the FDA Drug Label
In controlled clinical trials involving over 100 patients who received drug, 82% of patients treated for functional bowel/irritable bowel syndrome with dicyclomine hydrochloride at initial doses of 160 mg daily (40 mg four times daily) demonstrated a favorable clinical response compared with 55% treated with placebo (p<0.05). Dicyclomine is used to treat irritable bowel syndrome (IBS), and it has been shown to produce a favorable clinical response in 82% of patients, which is significantly better than the response to placebo 2.
- The medication is effective at an initial dose of 160 mg daily, divided into 40 mg four times daily.
- This indicates that dicyclomine can help alleviate symptoms of IBS.
From the Research
Dicyclomine for IBS
- Dicyclomine is an antispasmodic agent that has been studied for its effectiveness in treating Irritable Bowel Syndrome (IBS) symptoms 3, 4.
- A 1981 study found that dicyclomine hydrochloride 40 mg 4 times daily was superior to placebo in improving overall condition, decreasing abdominal pain, decreasing abdominal tenderness, and improving bowel habits in patients with IBS 3.
- A 2012 systematic review and meta-analysis found that antispasmodic agents, including dicyclomine, were effective in improving global symptoms and abdominal pain in IBS patients, with no significant adverse events 4.
- Dicyclomine is also mentioned as a treatment option for IBS in a 2014 review of medication management for IBS, although it is not listed as one of the most reliable evidence-supported treatments 5.
- More recent guidelines and reviews, such as the 2021 ACG Clinical Guideline for the management of IBS, do not specifically mention dicyclomine as a recommended treatment option 6, and instead focus on other therapies such as chloride channel activators, guanylate cyclase activators, and rifaximin.
Mechanism of Action
- The exact mechanism of action of dicyclomine in IBS is not fully understood, but it is thought to work by relaxing the muscles in the stomach and intestines, thereby reducing spasms and improving bowel habits 3, 4.
- Dicyclomine has anticholinergic properties, which can help to reduce abdominal pain and discomfort in IBS patients 3.