Bentyl (dicyclomine) vs Common IBS Alternatives - Effects, Costs & Best Use

• by Malcolm Hitchcock
• Oct 1, 2025
• 1 Comments

Bentyl (dicyclomine) vs Common IBS Alternatives - Effects, Costs & Best Use

People with irritable bowel syndrome (IBS) often try several pills before finding relief. Bentyl is a household name, but it’s not the only option on the market. This guide breaks down how Bentyl stacks up against the most popular alternatives, looking at how they work, typical dosing, side‑effects, cost in the UK and whether you need a prescription.

Quick Takeaways

• Bentyl (dicyclomine) is an anticholinergic that eases smooth‑muscle cramps but can cause dry mouth and dizziness.
• Buscopan (hyoscine butylbromide) works locally in the gut, so it has fewer systemic side‑effects.
• Enteric‑coated peppermint oil provides a natural spasm‑relief with a low side‑effect profile.
• Mebeverine is a selective smooth‑muscle relaxant that’s popular in the UK and doesn’t cross the blood‑brain barrier.
• Alosetron and eluxadoline are prescription‑only drugs reserved for severe cases of IBS‑D (diarrhoea‑predominant) or IBS‑M (mixed).
• Lubiprostone helps with constipation‑dominant IBS by increasing intestinal fluid secretion.
• Cost and availability vary: over‑the‑counter (OTC) options are cheaper but may be less potent than prescription drugs.

What is Bentyl (dicyclomine)?

Bentyl is an anticholinergic medication approved by the FDA and the UK MHRA for treating IBS‑type abdominal cramps. It blocks muscarinic receptors in the gastrointestinal (GI) tract, reducing involuntary smooth‑muscle contractions. The usual adult dose in the UK is 20mg three times daily, taken before meals.

How Bentyl works

By inhibiting acetylcholine, Bentyl lowers the frequency of spasm‑induced pain. Because it acts system‑wide, you may feel its effects elsewhere - dry mouth, blurred vision, or a fainting sensation are common “anticholinergic” side‑effects.

Key Alternatives

Below is a snapshot of the main competitors you’ll encounter when researching IBS relief.

Hyoscine butylbromide (Buscopan)

Buscopan is an antispasmodic that stays largely in the gut, limiting systemic exposure. The standard OTC dose in the UK is 10mg up to three times daily. It’s especially useful for crampy pain without the dry‑mouth side‑effect profile of Bentyl.

Peppermint oil (enteric‑coated)

Enteric‑coated peppermint oil capsules release menthol directly in the small intestine, where it relaxes smooth muscle by blocking calcium channels. A typical dose is 0.2mL (about two capsules) three times a day. It’s an OTC “natural” option with minimal serious side‑effects, though heartburn can occur in sensitive individuals.

Mebeverine

Mebeverine is a selective smooth‑muscle relaxant that does not affect the central nervous system. The UK dose is 135mg up to three times daily, taken with meals. It’s prescription‑only in many EU countries but available OTC in the UK for milder symptoms.

Alosetron

Alosetron is a serotonin‑2 antagonist approved for severe diarrhoea‑predominant IBS (IBS‑D) in women who haven’t responded to other treatments. The dose is 0.5mg twice daily, and it must be prescribed under a Risk Evaluation and Mitigation Strategy (REMS) because of rare ischemic colitis risk.

Eluxadoline

Eluxadoline combines a µ‑opioid receptor agonist with a δ‑opioid receptor antagonist, targeting abdominal pain and altered bowel habit in IBS‑D. The standard dose is 100mg twice daily with meals. It requires a prescription and carries warnings for pancreatitis in patients without a gallbladder.

Lubiprostone

Lubiprostone is a chloride channel activator that increases intestinal fluid secretion, helping constipation‑predominant IBS (IBS‑C). The typical dose is 8µg twice daily. It’s prescription‑only and can cause nausea, headache, and rarely, severe dehydration.

Comparison Table

Decision‑Making Checklist

• Symptom pattern: Cramp‑dominant (Bentyl, Buscopan, Peppermint) vs diarrhoea‑dominant (Alosetron, Eluxadoline) vs constipation‑dominant (Lubiprostone).
• Side‑effect tolerance: If you’re sensitive to dry mouth, avoid Bentyl. If you have heartburn, be cautious with peppermint oil.
• Prescription vs OTC: OTC options are cheaper and easier to start, but may be less potent for severe cases.
• Cost considerations: Bentyl sits in the low‑to‑mid price range; newer agents can exceed £150/month.
• Regulatory status: Some drugs (Alosetron, Eluxadoline) require specialist monitoring.

Practical Tips & Common Pitfalls

1. Start low, go slow. Begin with the lowest effective dose of any new medication and titrate upward only if needed.

2. Watch for drug interactions. Bentyl, for example, can enhance the effects of other anticholinergics (e.g., antihistamines).

3. Don’t mix anticholinergics. Combining Bentyl with Buscopan rarely adds benefit but can increase side‑effects.

4. Consider timing with meals. Most antispasmodics work best when taken 30 minutes before food.

5. Track symptoms. Use a simple diary (pain score, stool frequency, side‑effects) to compare how each agent works for you.

When to See a Professional

If you experience any of the following, stop the medication and contact your GP or a gastroenterology specialist:

• Severe constipation or inability to pass gas (possible sign of obstruction)
• Unexplained weight loss or blood in stool
• Signs of allergic reaction - rash, swelling, difficulty breathing
• Persistent dizziness or fainting episodes while on anticholinergics

Bottom Line

There’s no one‑size‑fits‑all answer. Bentyl works well for many people with crampy IBS, but its systemic side‑effects push some toward gut‑focused agents like Buscopan or natural options such as peppermint oil. For severe diarrhoea‑type IBS, prescription‑only drugs like Alosetron or Eluxadoline may be the only viable route, albeit with higher cost and monitoring needs. Evaluate your symptom pattern, budget, and tolerance for side‑effects, then discuss the options with a healthcare professional to land on the best fit.

Frequently Asked Questions

Can I use Bentyl and Buscopan together?

Generally it’s not recommended. Both act as antispasmodics, and combining them can increase the risk of dry mouth, constipation, or blurred vision without offering extra pain relief. Talk to your doctor before mixing.

Is peppermint oil safe for long‑term use?

Enteric‑coated peppermint oil is considered safe for most adults when taken as directed (up to three doses a day). People with severe GERD should be cautious because menthol can relax the lower oesophageal sphincter and worsen heartburn.

Why is Alosetron only for women?

Clinical trials showed a higher risk of severe constipation and ischemic colitis in men, so the FDA limited its approval to women with severe IBS‑D who failed other treatments.

Do I need a prescription for Mebeverine in the UK?

Mebeverine is available over‑the‑counter in many UK pharmacies, but a prescription may be required for higher strengths or if you’re buying it online.

Which IBS drug is cheapest in the UK?

Buscopan (hyoscine butylbromide) is the most affordable OTC option, typically costing under £5 for a month’s supply. Bentyl and Mebeverine are a bit pricier, while newer prescription drugs can exceed £150 per month.