Why do they give you Buscopan for MRI scan? Enhancing image clarity with antispasmodics

October 8, 2025 •

4 min read

In certain MRI scans, specifically those of the abdomen and pelvis, internal movement from bowel activity can cause motion artifacts that blur images. To counteract this, medical professionals may administer Buscopan to patients just before the scan, explaining why they give you Buscopan for MRI scan in these specific circumstances. By temporarily halting intestinal muscle spasms, this antispasmodic medication allows for the capture of clearer, more precise images.

Quick Summary

Buscopan (hyoscine butylbromide) is a medication administered before specific abdominal and pelvic MRI scans to relax the smooth muscles of the gastrointestinal tract. By reducing the involuntary bowel movements known as peristalsis, Buscopan minimizes motion artifacts and significantly enhances the diagnostic quality of the resulting images.

Key Points

Reduces motion artifacts: Buscopan is an antispasmodic medication that temporarily paralyzes the smooth muscles of the bowel and bladder, preventing involuntary movement (peristalsis) that can blur MRI images.
Improves diagnostic clarity: By minimizing internal motion, Buscopan enables radiologists to obtain clearer, sharper images of the abdominal and pelvic organs, which is crucial for accurate diagnosis.
Used for specific scans: The medication is most often used for imaging procedures where bowel movement is a major factor, such as MR enterography or pelvic MRI.
Administered via injection: For a quick and effective onset, Buscopan is injected intravenously just before the scan begins.
Consider contraindications and side effects: Medical staff screen for conditions like glaucoma or certain heart problems before administering Buscopan. Common side effects include temporary dry mouth and blurred vision.
Glucagon is an alternative: In some regions, or for patients with specific contraindications, glucagon is used as an alternative antispasmodic agent.
Patients are monitored after injection: Due to temporary side effects like blurred vision, patients are advised not to drive until symptoms subside, typically within a couple of hours.

Understanding Motion Artifacts in MRI

Magnetic Resonance Imaging (MRI) is a powerful diagnostic tool that uses magnetic fields and radio waves to create detailed images of organs and tissues. However, the quality of these images is highly dependent on the patient's stillness during the scan. While patients can consciously hold their breath to minimize movement, involuntary physiological processes, such as the rhythmic contractions of the intestines (peristalsis), can cause image blur and distortion. These distortions are known as motion artifacts and can obscure critical details, making accurate diagnosis more difficult. For imaging procedures focused on the abdominal and pelvic regions, where the bowel and other smooth-muscle organs are prominent, these motion artifacts present a significant challenge.

What is Buscopan and How Does it Work?

Buscopan, also known by its active ingredient hyoscine butylbromide, is an antispasmodic agent commonly used in radiological practice. When given intravenously before an MRI, it works by relaxing the smooth muscles of the digestive and urinary tracts.

The mechanism of action

Targeting smooth muscle: The medication targets the muscarinic acetylcholine receptors, primarily in the autonomic nervous system.
Inhibiting nerve impulses: By blocking the effect of the neurotransmitter acetylcholine, Buscopan inhibits the nerve impulses that signal smooth muscles to contract.
Reducing peristalsis: The result is a temporary cessation of involuntary muscle spasms in the intestines, bowels, and bladder. This "freezes" the bowel for a short period, allowing the scanner to capture clear, detailed pictures without interference from internal motion.

The Administration Process for an MRI Scan

For an MRI scan, Buscopan is administered as an injection, typically into a vein in the arm or back of the hand, just before the imaging sequence begins. The intravenous route ensures a rapid onset of action, with the muscle-relaxing effect starting within minutes. The effect is relatively short-lived, usually lasting between 15 and 30 minutes, which is sufficient for capturing the necessary images during the scan. The medical staff will explain the process and confirm that the patient has no contraindications before administering the medication.

Comparison: Buscopan vs. Glucagon

Buscopan is not the only antispasmodic agent used in diagnostic imaging. Glucagon is another option, particularly in regions where Buscopan may not be licensed or preferred. The choice between these two medications can depend on institutional preference, cost-effectiveness, and the patient's specific health profile.


Feature	Buscopan (Hyoscine Butylbromide)	Glucagon
Mechanism	Anticholinergic agent, relaxes smooth muscle by blocking muscarinic receptors.	Polypeptide hormone, inhibits intestinal motility via a different pathway.
Onset of Action (IV)	Quick, within minutes (some studies cite 28-85 seconds for maximal effect).	Very quick, within minutes (some studies cite 34-65 seconds for maximal effect).
Duration of Effect	Temporary, typically 15-30 minutes for effect, side effects may last 1-2 hours.	Slightly longer duration compared to Buscopan (e.g., 33 vs 24 minutes in one study).
Common Side Effects	Dry mouth, dizziness, temporary blurred vision, increased heart rate.	Nausea, vomiting, dizziness, hyperglycemia.
Availability	Widely used in Europe and other regions, often cheaper.	Used as an alternative, particularly in the US where Buscopan is not licensed for human use.
Cost	Generally more cost-effective than glucagon.	More expensive than Buscopan.

Key Considerations: Contraindications and Side Effects

While generally safe, Buscopan is not suitable for everyone. Before administration, medical staff will conduct a thorough screening for contraindications, which are conditions where the medication should not be used.

Important contraindications for Buscopan include:

Glaucoma: The medication can increase pressure within the eye.
Certain heart conditions: Including very fast or irregular heart rhythms.
Myasthenia gravis: A neuromuscular disorder.
Prostatic hypertrophy: In men with this condition, Buscopan can cause urinary retention.
Severe bowel obstruction: Conditions like paralytic ileus or megacolon.
Known allergy: To hyoscine butylbromide or any other ingredients.

Potential side effects

Most side effects are mild and temporary. After the injection, patients may experience:

Dry mouth
Dizziness or feeling faint
Temporary blurred vision
A temporary increase in heart rate

Due to the possibility of blurred vision, patients are advised not to drive or operate heavy machinery until their vision returns to normal, which typically takes a couple of hours.

Conclusion

In summary, Buscopan is a critical pharmacological tool used in specific MRI scans, particularly of the abdomen and pelvis. By temporarily relaxing the smooth muscles of the digestive system and reducing involuntary movements, it minimizes motion artifacts and allows for the capture of clear, high-quality images essential for accurate diagnosis. The decision to administer Buscopan is made by a radiologist or qualified medical professional after considering the patient's medical history and checking for contraindications. While it has common, short-lived side effects, the benefit of improved diagnostic image quality often outweighs these minor concerns. Patients should always feel free to discuss the procedure and any concerns with the medical team prior to their scan.

Frequently Asked Questions

Buscopan, also known by its active ingredient hyoscine butylbromide, is a medication that belongs to a class of drugs called antispasmodics. It relaxes the smooth muscles in the stomach, intestines, and bladder to relieve cramps and spasms.

No, Buscopan is not used for all MRI scans. It is typically reserved for scans of the abdomen and pelvis where bowel motion can significantly interfere with image quality. It is not necessary for scans of the brain, spine, or joints, for example.

For an MRI scan, Buscopan is usually given as a small injection into a vein, often in the arm. This provides a rapid and effective onset of action to relax the bowel muscles before the imaging begins.

The muscle-relaxing effect of the intravenous injection lasts for about 15 to 30 minutes, which is long enough for the scan. Some mild side effects, such as blurred vision or dry mouth, may last for up to an hour or two.

Common side effects are generally mild and temporary and include dry mouth, temporary blurred vision, dizziness, and a slightly increased heart rate.

No, you should not drive or operate machinery until any temporary blurred vision has completely worn off. Medical staff will advise you to wait and may have a designated waiting area for post-injection recovery.

Yes, Buscopan is not suitable for everyone. Important contraindications include having glaucoma, certain heart problems, myasthenia gravis, or a severe bowel obstruction. You will be screened by medical staff to ensure it is safe for you.

Yes, glucagon is another antispasmodic medication that can be used to relax the bowel during MRI, particularly in the United States where Buscopan is not licensed for human use. The choice of agent depends on institutional protocols and patient factors.