Mebeverine vs Buscopan vs Alverine: Antispasmodics Compared
The three IBS antispasmodics side by side — how they differ, who each one suits, the cautions that matter, and how to tell whether yours is working.
Part of the Complete IBS Guide.
Key fact: Antispasmodics treat the cramping of IBS, not the bowel habit. The main practical difference between them is that hyoscine butylbromide (Buscopan) is an anticholinergic, with the side effects and cautions that implies, while mebeverine and alverine act directly on gut muscle without them.
What antispasmodics do
The pain of IBS comes largely from the smooth muscle of the bowel wall contracting too hard and out of sequence, in a gut that reports those contractions more loudly than it should. Antispasmodics relax that muscle. They do not alter transit time, they do not treat constipation or diarrhoea, and they do not change the underlying condition — they take the edge off cramping and, indirectly, some of the bloating that goes with it.
That is worth being clear about, because it sets a realistic expectation. NICE positions antispasmodics as a first-line medicine in IBS alongside dietary and lifestyle change. They are a good first medicine precisely because they are low-risk and quick to judge, not because they are powerful.
The three compared
| Mebeverine | Hyoscine butylbromide (Buscopan) | Alverine citrate | |
|---|---|---|---|
| Class | Direct smooth-muscle relaxant | Antimuscarinic (anticholinergic) | Direct smooth-muscle relaxant |
| Typical adult dose | 135mg three times a day | 10mg three to four times a day (OTC), up to 20mg four times a day on prescription | 60–120mg one to three times a day |
| Timing | 20 minutes before meals | When symptoms occur or before a trigger | With or before meals |
| Best suited to | Predictable, meal-related cramping | Unpredictable, acute cramping episodes | Cramping with bloating; an alternative when mebeverine fails |
| Main drawbacks | Needs regular dosing to work well | Dry mouth, blurred vision, constipation; several cautions | Less familiar to patients; occasional nausea, headache |
None of the three is clearly superior across the board, and NICE does not rank them. The practical difference is the anticholinergic profile: mebeverine and alverine act locally on gut muscle with few systemic effects, while hyoscine butylbromide is an antimuscarinic and behaves like one.
Mebeverine
Mebeverine is the most widely prescribed antispasmodic for IBS in the UK. It acts directly on the smooth muscle of the gut without blocking acetylcholine, which is why it avoids the dry mouth and blurred vision that come with anticholinergics, and why it is generally the easiest of the three to tolerate.
The catch is that it works best as a regular medicine rather than a rescue one. Taken 20 minutes before meals, three times a day, it is pre-empting the post-meal contraction that causes the pain. Taken sporadically once the cramp has arrived, it underperforms — and that mismatch is the most common reason people conclude it has not worked. A modified-release preparation taken twice daily is also available.
It should not be used in paralytic ileus. We cover doses, timing and what to expect in more detail in what mebeverine is used for, and it is available as mebeverine tablets, as Colofac MR, and combined with ispaghula as Fybogel Mebeverine where constipation sits alongside the cramping.
Hyoscine butylbromide (Buscopan)
Hyoscine butylbromide blocks muscarinic receptors in gut smooth muscle, producing a stronger, faster relaxation than mebeverine. It suits people whose cramping arrives unpredictably rather than reliably after meals, and it can be taken when symptoms start rather than on a fixed schedule. Buscopan IBS Relief and Buscopan Cramps are the pharmacy versions; Buscopan tablets at higher strength are prescription.
Cautions that matter: because it is an anticholinergic, hyoscine butylbromide should be avoided in myasthenia gravis, megacolon and bowel obstruction, and used with caution in angle-closure glaucoma, in men with prostatic enlargement or difficulty passing urine, and in people with a rapid heart rate. It also adds to the load if you already take other anticholinergic medicines — some antihistamines, tricyclic antidepressants and bladder medicines among them. Check with a pharmacist if any of these apply.
Constipation is a predictable side effect, which makes it a poorer fit for IBS-C and a reasonable one for IBS-D, where the same effect is useful. Dry mouth and blurred vision are the other common complaints.
Alverine citrate
Alverine is the least familiar of the three to most patients and works much like mebeverine — direct relaxation of gut smooth muscle without anticholinergic effects. It is a sensible second choice when mebeverine has been taken properly for a few weeks and has not delivered, and it is often described as helping bloating alongside pain. Alverine citrate capsules are available in the UK; it should not be used in paralytic ileus, and nausea, headache and dizziness are the side effects worth knowing about.
Peppermint oil: the fourth option
Enteric-coated peppermint oil is not usually grouped with the antispasmodics, but it works by the same mechanism — menthol relaxes gut smooth muscle — and it has the best trial evidence of any of these options for bloating and abdominal pain specifically. The enteric coating exists so the oil is released in the intestine rather than the stomach.
The main drawback is heartburn: peppermint relaxes the lower oesophageal sphincter as well, so it can aggravate reflux. If you have both IBS and reflux, that trade-off is worth weighing — our acid reflux page covers the other side of it. Apercap peppermint oil capsules are one of the UK preparations.
Which to try first, and how to judge it
1
Match the medicine to the pattern
Predictable post-meal cramping suits mebeverine taken before meals. Unpredictable episodes suit hyoscine butylbromide taken as needed. Bloating with pain suits peppermint oil.
2
Take it properly for two to four weeks
Most apparent failures are dosing failures — taken irregularly, or after the pain rather than before the meal that causes it.
3
Judge it against a symptom diary
IBS fluctuates on its own, so impressions are unreliable. Two weeks of recorded pain scores before and during treatment give you a real answer.
4
Switch rather than stack
If one has genuinely failed at the right dose, try another class rather than adding a second on top.
When antispasmodics are not enough
Antispasmodics treat pain, so if your dominant problem is stool form they will disappoint. Diarrhoea is treated with loperamide, constipation with an osmotic laxative such as macrogol — not lactulose, which NICE advises against in IBS because it ferments. Where pain persists despite an antispasmodic taken properly, NICE moves to a low-dose tricyclic antidepressant such as amitriptyline, used at doses far below those for depression and specifically for their effect on gut pain signalling, with an SSRI as an alternative. Psychological therapies including CBT and gut-directed hypnotherapy are recommended where symptoms have not responded after 12 months.
Diet remains the other main lever: see the low FODMAP diet, phase by phase, and IBS-D, IBS-C and IBS-M for how subtype changes the plan.
Stop and see a GP if you develop unexplained weight loss, rectal bleeding or black stools, diarrhoea that wakes you at night, a change in bowel habit lasting six weeks or more over the age of 60, or new IBS-type symptoms over the age of 50. These are not IBS symptoms and no antispasmodic is the right answer to them.
Frequently Asked Questions
Which is better for IBS, mebeverine or Buscopan?
Neither is better across the board and NICE does not rank them. Mebeverine suits predictable, meal-related cramping and is taken regularly before meals; Buscopan works faster and suits unpredictable cramping taken as needed. The deciding factor is usually tolerability: Buscopan is an anticholinergic, so it can cause dry mouth, blurred vision and constipation, and carries cautions that mebeverine does not.
How long does mebeverine take to work?
It acts within an hour of a dose, but judging whether it helps takes two to four weeks of taking it properly — 135mg three times a day, twenty minutes before meals. Taken irregularly or only once cramping has started, it consistently underperforms, and that is the most common reason people believe it has not worked for them.
Can I take an antispasmodic and peppermint oil together?
They work by similar mechanisms, so combining them adds little and makes it impossible to tell which is helping. It is more useful to trial one properly for two to four weeks, judge it against a symptom diary, and switch rather than stack if it fails. A pharmacist can check the combination against your other medicines if you want to try both.
Who should not take Buscopan?
Hyoscine butylbromide should be avoided in myasthenia gravis, megacolon and bowel obstruction, and used with caution in angle-closure glaucoma, in men with prostate enlargement or difficulty passing urine, and in people with a fast heart rate. It also adds to the anticholinergic burden of medicines such as some antihistamines, tricyclic antidepressants and bladder medicines. Check with a pharmacist if any of these apply to you.
Do antispasmodics help bloating as well as pain?
Indirectly. They relax the gut muscle rather than removing gas, so they ease the cramping component of bloating rather than the distension itself. Enteric-coated peppermint oil has the better evidence where bloating rather than pain is the dominant symptom, and treating constipation, if present, usually does more than either.
Are antispasmodics safe to take long term?
Mebeverine and alverine are generally well tolerated over long periods and are not habit-forming. Long-term regular use of an anticholinergic such as hyoscine butylbromide deserves more thought, particularly in older people, because anticholinergic effects accumulate across medicines. Either way, IBS treatment should be reviewed periodically rather than repeated indefinitely without discussion.
References
- National Institute for Health and Care Excellence. Irritable bowel syndrome in adults: diagnosis and management (CG61). nice.org.uk
- National Institute for Health and Care Excellence. Suspected cancer: recognition and referral (NG12). nice.org.uk
- NHS. Irritable bowel syndrome (IBS): diet, lifestyle and medicines. nhs.uk
- Monash University. Starting the low FODMAP diet. monashfodmap.com
- National Institute for Health and Care Excellence. Coeliac disease: recognition, assessment and management (NG20). nice.org.uk
Medical disclaimer: This article is for informational purposes only and does not constitute medical advice. IBS should be diagnosed by a clinician who has excluded the conditions that mimic it. Always consult a qualified healthcare professional for diagnosis and treatment. In a medical emergency, call 999.