Hyoscine Butylbromide (Buscopan)
Is It Right for You?
A complete guide to Hyoscine Butylbromide (Buscopan) — what it treats, how it works, dosages, side effects, and when a clinician may prescribe it following an online consultation.
What Is Hyoscine Butylbromide (Buscopan)?
Hyoscine butylbromide, commonly known by its brand name Buscopan, is an anticholinergic (antimuscarinic) antispasmodic medication used to relieve smooth muscle spasm in the gastrointestinal, biliary, and urinary tracts. It is one of the most widely used treatments for abdominal cramping and spasm-related pain, including that associated with irritable bowel syndrome (IBS), biliary colic, and renal colic.
A key pharmacological feature of hyoscine butylbromide is its quaternary ammonium chemical structure, which prevents it from crossing the blood-brain barrier. This means it exerts its antispasmodic effects peripherally — on the smooth muscle of the gut and urinary tract — without producing the central nervous system effects (such as sedation, hallucinations, or confusion) associated with scopolamine (hyoscine hydrobromide), its centrally-acting counterpart.
Available over the counter in lower doses for self-treatment of IBS cramping, hyoscine butylbromide is also available on prescription at higher doses and is used by injection in hospital settings — for example, as a smooth muscle relaxant during endoscopic and radiological procedures. It is suitable for adults and children over 6 years of age.
Higher-dose and injectable forms of hyoscine butylbromide are prescription-only medications in the UK. A licensed clinician must assess your symptoms and medical history before prescribing — which can now be done quickly and conveniently through a telehealth consultation.
What Conditions Is Hyoscine Butylbromide Used For?
Hyoscine butylbromide is prescribed for:
relief of abdominal cramping, bloating, and spasm associated with IBS.
generalised gut spasm causing abdominal pain and cramping from any cause.
acute spasmodic pain caused by gallstones obstructing the bile duct or gallbladder neck
spasmodic pain caused by kidney stones passing through the ureter.
painful periods caused by uterine cramping; used off-label but commonly prescribed.
intravenous/intramuscular hyoscine butylbromide is used in hospital settings to relax smooth muscle for improved visualisation during colonoscopy, CT colonography, barium enema, and MRI of the abdomen.
Hyoscine butylbromide relieves the symptom of smooth muscle spasm and associated pain. It does not treat the underlying cause of your symptoms. If abdominal pain is severe, persistent, or accompanied by other concerning symptoms such as blood in stools, unexplained weight loss, or fever, seek medical assessment to identify the cause.
How Does Hyoscine Butylbromide Work?
Hyoscine butylbromide competitively and reversibly blocks muscarinic acetylcholine receptors (specifically M1 and M3 subtypes) on smooth muscle cells and exocrine glands throughout the gastrointestinal, biliary, and urinary tracts.
In normal physiology, the neurotransmitter acetylcholine binds to muscarinic receptors on smooth muscle cells, triggering contraction. In conditions such as IBS or colic, this smooth muscle becomes hyperactive, producing painful, sustained spasms. By blocking muscarinic receptors, hyoscine butylbromide prevents acetylcholine from binding, inhibiting smooth muscle contraction and allowing spasming tissue to relax.
Because hyoscine butylbromide is a quaternary ammonium compound with very poor lipid solubility and low oral bioavailability, it is largely confined to the gut lumen and peripheral tissues after oral administration. It does not cross the blood-brain barrier in clinically significant amounts, meaning it produces no central anticholinergic effects such as sedation, confusion, or hallucinations. After intramuscular or intravenous administration, some peripheral anticholinergic effects such as dry mouth, tachycardia, and blurred vision may be more prominent.
Dosages & Administration
The correct dose depends on the type and severity of infection, age, weight, and kidney function. Always follow your clinician's instructions. The table below is for general reference only.
Administration Tips
Take oral tablets with water — they can be taken with or without food, though taking them before meals may be beneficial for gastrointestinal spasm related to eating.
For IBS, hyoscine butylbromide is most effective when taken regularly before meals rather than just when cramps occur, as it prevents spasm from developing.
Tablets should be swallowed whole with water — do not chew.
For occasional cramping, a single dose of 10–20 mg can be taken as required when symptoms occur.
Do not use if you have been told you have a bowel obstruction, severe constipation, toxic megacolon, or known narrow-angle glaucoma — inform your clinician of these conditions before starting treatment.
Side Effects of Hyoscine Butylbromide
At standard oral doses, hyoscine butylbromide is well tolerated. Because it is poorly absorbed from the gastrointestinal tract, systemic anticholinergic side effects are generally mild at oral doses. They are more pronounced with parenteral (injectable) administration.
- Dry mouth
- Tachycardia (rapid heart rate)
- Urinary hesitancy or retention
- Constipation
- Blurred vision (accommodation difficulty)
- Flushing and warm skin
- Acute angle-closure glaucoma — sudden, severe eye pain, blurred vision, halos around lights, nausea; hyoscine butylbromide can precipitate acute angle-closure glaucoma by dilating the pupil in susceptible individuals
- Urinary retention — inability to pass urine; risk is highest in men with prostate enlargement
- Tachyarrhythmias — particularly with higher doses or parenteral administration; caution in patients with cardiac conditions
- Paralytic ileus — excessive bowel relaxation causing cessation of gut motility; rare
- Anaphylaxis — rare severe allergic reaction
Hyoscine butylbromide causes pupil dilation (mydriasis), which can precipitate acute angle-closure glaucoma in individuals with anatomically narrow anterior chamber angles. If you have been told you have narrow-angle glaucoma or are at risk of it, do not use hyoscine butylbromide without ophthalmological assessment. Angle-closure glaucoma is a medical emergency requiring urgent treatment.
Drug Interactions
Always disclose all prescription drugs, over-the-counter medicines, vitamins, and supplements to your clinician or pharmacist before starting hyoscine butylbromide.
Additive anticholinergic effects, increasing the risk of dry mouth, urinary retention, constipation, tachycardia, and — particularly in elderly patients — confusion and cognitive impairment.
These prokinetic agents accelerate gastrointestinal motility; hyoscine butylbromide directly antagonises this effect, reducing their efficacy if taken concurrently.
Has anticholinergic properties; additive anticholinergic effects when combined with hyoscine butylbromide.
Additive anticholinergic effects; monitor for increased side effects.
No direct pharmacological interaction, but alcohol may worsen dehydration and general gastrointestinal symptoms; limit consumption during treatment.
Important Warnings
Hyoscine butylbromide causes pupil dilation and can precipitate acute angle-closure glaucoma in susceptible individuals. Symptoms of acute angle-closure glaucoma include sudden severe eye pain, redness of the eye, blurred vision, haloes around lights, and nausea. This is a medical emergency. Do not use hyoscine butylbromide if you have narrow-angle glaucoma.
In men with benign prostatic hyperplasia (enlarged prostate) or other causes of outflow obstruction, hyoscine butylbromide may precipitate acute urinary retention — the sudden inability to pass urine. This is a medical emergency. Inform your clinician if you have prostate problems or difficulty urinating before starting treatment.
Hyoscine butylbromide is contraindicated in patients with known or suspected mechanical bowel obstruction or paralytic ileus. By reducing bowel motility, it may worsen these conditions. Severe or colicky abdominal pain associated with constipation, distension, and vomiting requires urgent medical assessment before starting any antispasmodic.
Antimuscarinic drugs including hyoscine butylbromide may exacerbate myasthenia gravis — a condition causing muscle weakness due to impaired neuromuscular transmission. Inform your clinician if you have myasthenia gravis before starting treatment.
There is limited controlled data on hyoscine butylbromide use in pregnancy. Its use is generally restricted to situations where the benefit clearly outweighs potential risk. It is used in some clinical settings during labour to facilitate cervical dilation; discuss with your clinician. Small amounts may pass into breast milk; breastfeeding during treatment should be discussed with your clinician.
Speak to a Clinician About Treatment
Getting advice no longer means sitting in a waiting room. Through The GP Service, you can consult with a licensed clinician in minutes — from home, on your lunch break, or wherever works for you. If treatment is clinically appropriate, your clinician can issue a prescription during the consultation. A consultation does not guarantee a prescription.
The treatment you need, when you need it.
Hyoscine Butylbromide FAQs
Standard Buscopan tablets contain 10 mg of hyoscine butylbromide and are available over the counter for self-treatment of IBS and abdominal cramps. Buscopan Forte (or prescription-strength formulations) contain 20 mg and are available on prescription for more severe spasm. Your clinician will advise on the appropriate dose and strength for your condition.
Both are forms of hyoscine, but they have very different pharmacological profiles. Hyoscine hydrobromide (scopolamine) crosses the blood-brain barrier and produces central anticholinergic effects including sedation, anti-nausea effects, and — at toxic doses — confusion and hallucinations. It is used for travel sickness and as a pre-anaesthetic. Hyoscine butylbromide does not cross the blood-brain barrier significantly, acts only peripherally on smooth muscle, and causes no central effects. It is safer and more targeted for gastrointestinal conditions.
After an oral dose, hyoscine butylbromide typically begins to relieve cramping and spasm within 15 to 30 minutes, though its poor oral bioavailability means the effect may be more modest than with the intramuscular or intravenous route. Injected forms work within minutes and are used for rapid spasm relief in hospital settings.
Hyoscine butylbromide can be taken regularly for IBS management — some patients take it before meals to prevent spasm. It is generally considered safe for regular use, but persistent or worsening symptoms should be reviewed by a clinician to ensure the diagnosis is correct and that other contributing factors are addressed. Long-term reliance on any antispasmodic without addressing dietary and lifestyle factors is not ideal.
No. Because hyoscine butylbromide does not cross the blood-brain barrier, it does not cause sedation or drowsiness. This makes it safe to take when driving or operating machinery, unlike some other medications used for pain or nausea.
Hyoscine butylbromide tablets are suitable for children aged 6 years and over. The dose for children aged 6 to 12 is typically 10 mg up to three times daily. It should not be used in children under 6 years. A clinician should assess and prescribe for paediatric use.