Drug Interaction Report

Belladonna and Bethanechol: Interaction Details

Name: Belladonna and Bethanechol Interaction
Creator: Dr. Brian Staiger, PharmD, BCPS

A pharmacist-reviewed analysis of the Belladonna and Bethanechol interaction: the documented clinical effects, severity rating, onset, mechanism, and management considerations, with cited references throughout.

AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature

Belladonna

No brand names on record

Bethanechol

Duvoid® Myotonachol® Urecholine®

Medically reviewed by

Dr. Brian Staiger, PharmD, BCPS

Updated Aug 8, 2026

Editorial policy · Data sources

Interaction severity

Minor

Usually limited clinical impact.

Minor

Moderate

Major

Contraindicated

How we grade severity & evidence

Severity levels

Contraindicated: These should generally not be used together.
Major: Potentially serious — often needs a change or close monitoring.
Moderate: Can be significant — usually manageable with monitoring.
Minor: Usually limited clinical impact.

Evidence grades

Established: Well documented — supported by controlled studies or strong clinical data.
Probable: Good supporting evidence, though not definitively proven.
Suspected: Some evidence suggests this interaction, but it is not well established.
Possible: Limited or conflicting evidence; the interaction may occur.
Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.

Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.

Of 18 documented Belladonna interactions, 7 are rated minor — including this one.

Onset

rapid

Evidence

theoretical

Severity

Minor

What happens

Reduced effectiveness of bethanechol

Interaction Deep Dive

The anticholinergic activity of the active alkaloids present in belladonna may reduce the effectiveness of bethanechol. Belladonna contains L-hyoscyamine, atropine, and scopolamine with a total alkaloid content of at least 0.3% in the leaves and 0.5% in the roots¹. Because belladonna is typically available as a homeopathic preparation, the clinical severity of the interaction with bethanechol is unknown. Caution is advised.

Why it happens (mechanism)

Anticholinergic effect of belladonna may counteract the cholinergic effect of bethanechol

Common questions

Can I take Belladonna and Bethanechol together?

Reduced effectiveness of bethanechol Always confirm with your pharmacist or prescriber before making any change.

How serious is the Belladonna and Bethanechol interaction?

It is rated minor. Usually limited clinical impact.

How quickly could this interaction happen?

The documented onset is "rapid". Effects can appear quickly, often within about 24 hours of combining the drugs.

How strong is the evidence for this interaction?

The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.

Questions for your pharmacist

Does my dose of Belladonna or Bethanechol need adjusting while I take them together?
What symptoms should prompt me to call you or my prescriber right away?
Does the timing of my doses matter for this combination?
Is there anything you'd monitor while I'm on both?

References (1)

Blumenthal, M, Busse WR, et alBlumenthal, M, Busse WR, et al (Eds): The Complete German Commission E Monographs, 1st. American Botanical Council, Austin, TX, 1998, pp 87-88.

Was this write-up helpful?

Belladonna

Keep reading about Belladonna

All Belladonna interactions (18)

Also serious with: Acetaminophen And Codeine Morphine Injection Hydromorphone Injection Glucagon Injection

Bethanechol

Keep reading about Bethanechol

All Bethanechol interactions (7) Bethanechol drug information

Check another combination

Our instant two-drug interaction checker is almost here.

Coming soon

The instant two-drug checker is on its way.

In the meantime, browse the directory below to look up any drug and see its documented interactions.

Still have questions about this combination?

Every question gets a real answer from a licensed pharmacist — free, and usually within a day.

Ask the pharmacist

A message from HelloPharmacist

About our interaction database: depth, not breadth

HelloPharmacist doesn't license one of the big commercial interaction databases, so what you'll find here is not a complete list of every known drug interaction. Instead, each entry is researched, analyzed, and written up individually — documented from the published literature, reviewed by a pharmacist, and cited so you can check every source yourself.

If a combination isn't listed here, it means we haven't documented it yet — never that it's safe. For screening a full medication list, we recommend pairing this site with a comprehensive tool like the Drugs.com Interaction Checker and, most importantly, a review by your own pharmacist. For a deep, plain-English, fully sourced explanation of a specific documented interaction — that's exactly what we built this for.

This information is for education, not a substitute for professional medical advice. Do not start, stop, or change any medication without talking to your pharmacist or prescriber.