Bentyl (Dicyclomine) 10 mg Capsules and 20 mg Tablets: Prescription Anticholinergic Antispasmodic for IBS Abdominal Cramping, Bowel Hypermotility, and Intestinal Spasm

Information last reviewed: May 2026 — for educational purposes only.

Bentyl (dicyclomine hydrochloride) is a prescription anticholinergic antispasmodic used to treat the painful abdominal cramping and bowel spasm associated with irritable bowel syndrome (IBS). It works by blocking muscarinic acetylcholine receptors (M1 and M3 subtypes) in smooth muscle of the gastrointestinal tract, reducing excessive bowel contractions and intestinal motility that cause cramping and pain. Dicyclomine is one of the most commonly prescribed antispasmodics in the US for IBS abdominal pain and is available in capsule, tablet, syrup, and injection forms.

IBS is a chronic functional gastrointestinal disorder characterised by recurrent abdominal pain, bloating, and altered bowel habits (diarrhoea, constipation, or mixed pattern) without identifiable structural organic disease. Dicyclomine provides symptomatic relief of the spasm component of IBS pain — it does not cure or modify the underlying condition. It is typically used for acute treatment of cramping episodes rather than continuously long-term, due to the development of tolerance to its antispasmodic effects and the side effect burden of chronic anticholinergic use.

What Is Dicyclomine?

Dicyclomine is a synthetic anticholinergic (antimuscarinic) compound that blocks acetylcholine's action on smooth muscle M-type receptors in the gut. This reduces the frequency and intensity of intestinal contractions and spasms. The drug has a relatively selective action on GI smooth muscle at therapeutic doses compared to systemic anticholinergics used for other purposes, but still produces typical anticholinergic side effects — dry mouth, blurred vision, urinary retention, constipation, and tachycardia — particularly at higher doses. It does not cross the blood-brain barrier to a significant extent at standard doses, limiting CNS anticholinergic effects compared to agents like scopolamine.

Prescription Status

Dicyclomine is prescription-only in the United States. It is not available OTC. A physician evaluation for abdominal symptoms is important to distinguish IBS from other conditions (IBD, colorectal cancer, coeliac disease) before prescribing long-term antispasmodics.

Strengths and Available Forms

• 10 mg capsules — standard starting dose; taken 4 times daily initially then adjusted; 10 mg QID starting dose recommended for first week to assess tolerability
• 20 mg tablets — maintenance dose after establishing tolerability; 20 mg QID (80 mg/day) is the most commonly effective adult dose; max 160 mg/day but higher doses rarely needed and increase side effect burden
• 10 mg/5 mL syrup — for patients who cannot swallow capsules/tablets; same dosing schedule
• 10 mg/mL intramuscular injection — short-term hospital use only (typically 10–20 mg IM Q4–6H); NOT for IV administration

Dosing protocol: Start at 10 mg QID for one week to assess tolerance. If tolerated and inadequately effective, increase to 20 mg QID. Doses are typically taken 30 minutes before meals and at bedtime (before the post-meal peristaltic waves that trigger cramping). If dry mouth, urinary retention, or other anticholinergic effects become intolerable, reduce dose or discontinue.

Price of Bentyl / Generic Dicyclomine

Generic dicyclomine capsules and tablets are available at low to moderate cost at most US pharmacies. Many insurance plans cover generic dicyclomine. Brand-name Bentyl is more expensive. Without insurance, generic dicyclomine is accessible through pharmacy discount programs at modest cost.

Frequently Asked Questions

Who should not take dicyclomine?

Dicyclomine is contraindicated in: infants under 6 months (serious respiratory distress and cardiovascular side effects have been reported); patients with unstable cardiovascular conditions (tachyarrhythmia); narrow-angle glaucoma (anticholinergics increase intraocular pressure); obstructive uropathy (urinary retention risk); obstructive GI disease (pyloric stenosis, intestinal obstruction); severe ulcerative colitis (risk of toxic megacolon); myasthenia gravis; breastfeeding (secreted in breast milk, can cause infant apnoea). It should be used with caution in prostatic hypertrophy (urinary retention risk) and in the elderly (anticholinergic drugs increase fall risk and cognitive impairment risk in older patients — Beers Criteria lists it as potentially inappropriate in elderly patients).

How does dicyclomine differ from hyoscine (scopolamine) or hyoscyamine for IBS?

All three are anticholinergic antispasmodics used for GI cramping. Dicyclomine has a more selective GI smooth muscle action and less CNS penetration than scopolamine (which is used for motion sickness via its CNS activity). Hyoscyamine (Levsin) is the active isomer of atropine and is very similar to dicyclomine in mechanism. Hyoscyamine is available in sublingual form for rapid onset, which can be advantageous for acute cramping episodes. The choice between them largely depends on physician preference, formulary availability, and patient tolerability profile.

Does dicyclomine help diarrhoea-predominant IBS (IBS-D)?

Dicyclomine can be beneficial for IBS-D because reducing colonic motility and spasm reduces the urgency, frequency, and pain associated with diarrhoea-predominant bowel habits. However, at higher doses, its constipating effect (from reduced bowel motility) may overcorrect to constipation, particularly in IBS-mixed patients. Newer IBS-D specific treatments (rifaximin, alosetron for women, eluxadoline) may provide more targeted IBS-D relief with fewer anticholinergic side effects. Dicyclomine remains a useful, affordable first-line antispasmodic option, especially for pain and cramping as the predominant symptoms.

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