What medication cannot be taken with Buscopan? A Guide to Drug Interactions

October 12, 2025 •

4 min read

According to the UK's National Health Service (NHS), certain medicines for nausea, such as metoclopramide or domperidone, should not be taken with Buscopan because they counteract each other. Understanding what medication cannot be taken with Buscopan is vital for preventing reduced effectiveness or dangerous side effects, especially if you have existing health conditions.

Quick Summary

This article details key medications to avoid while taking Buscopan, including dopamine antagonists like metoclopramide, specific antidepressants, heart medicines, and other anticholinergic drugs, and explains why these interactions occur.

Key Points

Antagonistic Drug Interactions: Avoid taking Buscopan with medications that speed up gut movement, such as metoclopramide or domperidone, as they cancel each other's effects out.
Potentiated Side Effects: Combining Buscopan with other anticholinergic drugs, like some antidepressants and antihistamines, can significantly increase the risk of side effects such as dry mouth, blurred vision, and constipation.
Cardiovascular Risks: Buscopan can increase heart rate, making it potentially dangerous for individuals with pre-existing heart conditions, including heart failure, coronary heart disease, and arrhythmia.
Specific Injection Contraindication: The intramuscular injection form of Buscopan is contraindicated for patients on blood thinners like warfarin or heparin due to the risk of bleeding.
Healthcare Consultation: Always consult a doctor or pharmacist before starting Buscopan to review all other medications, including over-the-counter and herbal supplements, to prevent adverse interactions.

Understanding Buscopan's Mechanism and Interactions

Buscopan, known generically as hyoscine butylbromide, is an antispasmodic medication used to relieve cramps and spasms in the gastrointestinal and urinary tracts. It works by blocking the action of acetylcholine, a chemical that causes muscle contractions. This anticholinergic effect helps to relax the smooth muscles of the gut, providing relief from conditions like irritable bowel syndrome (IBS). However, this very mechanism is what makes it incompatible with several other classes of drugs, leading to two primary types of interactions: antagonism (where one drug cancels out the other) and potentiation (where the effects and side effects of both drugs are intensified).

Medications That Counteract Buscopan's Effects

The most straightforward and clinically significant interaction is with medications that have an opposite effect on gut motility. These should be strictly avoided in combination with Buscopan.

Dopamine Antagonists: Drugs like metoclopramide and domperidone are used to increase the movement of food through the gut to prevent nausea and vomiting. Because Buscopan's purpose is to slow down gut motility, taking these medications together renders both ineffective at their intended jobs.
Other IBS Remedies: Combining Buscopan with other antispasmodics for IBS is generally not recommended unless advised by a doctor. Doing so is unlikely to provide additional relief and could increase the risk of side effects.

Medications That Intensify Anticholinergic Side Effects

Taking Buscopan with other drugs that have anticholinergic properties can lead to an amplified effect, significantly increasing the risk of side effects like dry mouth, blurred vision, constipation, and difficulty urinating. This additive effect can be particularly dangerous for the elderly or those with pre-existing conditions.

Tricyclic and Tetracyclic Antidepressants: These medications, such as amitriptyline and doxepin, have strong anticholinergic properties that can be intensified when combined with Buscopan, increasing side effect risk.
Antihistamines: Certain antihistamines used for allergies or travel sickness (like diphenhydramine) have anticholinergic effects that can be additive when taken with Buscopan.
Antipsychotics: Medications for severe mental illness, including clozapine and chlorpromazine, also possess anticholinergic properties.
Medicines for Parkinson's Disease: Amantadine, used for Parkinson's and certain flu infections, can also increase the risk of anticholinergic side effects.
Asthma Medications: Inhaled medicines for breathing problems, such as tiotropium and ipratropium, have anticholinergic components that can interact with Buscopan.
MAO Inhibitors: Monoamine oxidase inhibitors (MAOIs) used for depression can also have their anticholinergic effects potentiated by Buscopan.

Medications and Conditions Affecting the Heart

Buscopan can cause an increase in heart rate (tachycardia). This can be particularly dangerous for individuals with pre-existing cardiac conditions. Extreme caution or avoidance is necessary for patients with heart failure, coronary heart disease, cardiac arrhythmia, or hypertension.

Anti-arrhythmic Drugs: Medications used to control heart rhythm, such as quinidine and disopyramide, interact with Buscopan and can increase the anticholinergic effects.
Beta-adrenergic Agents: Medicines like salbutamol, used for asthma, can induce tachycardia, which is a side effect that can be enhanced by Buscopan.

Other Important Interactions

Blood Thinners: For the injectable form of Buscopan, particularly when administered intramuscularly, there is a specific contraindication for patients on anticoagulant drugs like warfarin or heparin, as this can cause intramuscular hematoma.
Alcohol and CNS Depressants: Alcohol and other central nervous system (CNS) depressants can increase the risk of drowsiness and dizziness, and should be used with caution.

Comparison of Common Drug Interactions with Buscopan


Medication Class	Example Drugs	Type of Interaction	Effect
Dopamine Antagonists	Metoclopramide, Domperidone	Antagonistic	Reduced efficacy: Buscopan slows gut motility, while these drugs increase it. They cancel each other out.
Tricyclic Antidepressants	Amitriptyline, Doxepin	Potentiation / Additive	Increased anticholinergic side effects: Raises the risk of dry mouth, blurred vision, constipation, and urinary retention.
Antihistamines	Diphenhydramine	Potentiation / Additive	Increased anticholinergic side effects: Compounding effects lead to intensified side effects.
Heart Medications	Quinidine, Disopyramide	Potentiation	Cardiovascular effects: Can exacerbate heart rate issues, particularly dangerous for those with pre-existing heart conditions.
Beta-Adrenergic Agents	Salbutamol (asthma inhaler)	Potentiation	Increased heart rate (tachycardia): Buscopan can enhance the tachycardic effects of these drugs.
Blood Thinners (Injectable)	Warfarin, Heparin	Contraindicated	Increased risk of bleeding: Intramuscular injections of Buscopan can cause hematoma in patients on anticoagulants.

Conclusion

While Buscopan is an effective treatment for stomach cramps and spasms, it is crucial to be aware of the medications that can interact with it. The most critical interactions include the antagonistic effect with drugs like metoclopramide and the potentiation of anticholinergic side effects with various antidepressants, antihistamines, and antipsychotics. Furthermore, individuals with existing heart conditions must exercise caution due to the risk of increased heart rate. Always consult a healthcare professional or pharmacist to review your complete medication list before taking Buscopan to ensure your safety and the medication's effectiveness.

For more detailed information, consult the official Patient Information Leaflet (PIL) for Buscopan IBS Relief on the eMC website: Buscopan IBS Relief - Patient Information Leaflet (PIL) - (emc) | 3884.

Frequently Asked Questions

No, you should not take Buscopan with metoclopramide. Buscopan works by slowing down gut movement, while metoclopramide increases it. Taking them together means they will counteract each other's effects, and neither medication will work properly.

No, it is not safe to take Buscopan with tricyclic or tetracyclic antidepressants like amitriptyline. Both have anticholinergic properties, and combining them can significantly increase side effects such as dry mouth, blurred vision, and difficulty urinating.

Buscopan should be used with caution, if at all, with heart medications such as quinidine and disopyramide, as it can potentially cause an increase in heart rate (tachycardia). This is especially dangerous for patients with pre-existing heart conditions.

Some antihistamines, particularly those used for allergies and motion sickness, also have anticholinergic effects. Combining them with Buscopan can lead to an additive effect and increase side effects like drowsiness, dry mouth, and blurred vision.

If you are on blood thinners like warfarin or heparin, the intramuscular injection form of Buscopan is contraindicated. The injection can cause a bleed (hematoma) within the muscle tissue, a risk that is much higher with blood thinners.

If you are taking any medication that interacts with Buscopan, you should speak with your doctor or pharmacist. They can advise you on the best course of action, which may involve switching medications, adjusting dosages, or using an alternative treatment.

Yes. Certain asthma medications, including beta-adrenergic agents like salbutamol and anticholinergics like ipratropium, can interact with Buscopan. The combination can enhance the tachycardic effects and increase other anticholinergic side effects.