Drug & supplement interaction

Bishop's Weed + Oxybutynin

Oxybutynin brand names: Ditropan, Ditropan XL, Oxybutynin, Oxytrol, Anturol, and others.

Moderate Interaction
Medically reviewed by · Updated October 2026
The bottom line Moderate

Bishop's Weed has a moderate interaction with Oxybutynin. Bergapten, a constituent of bishop's weed, has been shown to inhibit cytochrome P450 3A4 (CYP3A4) in vitro.

Read the full interaction report
SeverityModerate
LikelihoodPossible
EvidenceB
What do Severity, Likelihood & Evidence mean?
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Interaction report

Bishop's Weed and Oxybutynin

Here is the interaction we found between these two, with the evidence behind it.

Moderate

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

Why this applies to Oxybutynin

Oxybutynin falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES — the group Bishop's Weed interacts with.

Bergapten, a constituent of bishop's weed, has been shown to inhibit cytochrome P450 3A4 (CYP3A4) in vitro. Theoretically, bishop's weed might inhibit elimination and increase blood levels of drugs metabolized by CYP3A4.
Some drugs metabolized by CYP3A4 include alprazolam (Xanax), amitriptyline (Elavil), amiodarone (Cordarone), buspirone (Buspar), cerivastatin (Baycol), citalopram (Celexa), felodipine (Plendil), fexofenadine (Allegra), itraconazole (Sporanox), ketoconazole (Nizoral), lansoprazole (Prevacid), losartan (Cozaar), lovastatin (Mevacor), ondansetron (Zofran), prednisone (Deltasone, Orasone), sertraline (Zoloft), sibutramine (Meridia), sildenafil (Viagra), simvastatin (Zocor), verapamil (Calan, Covera-HS, Isoptin), and many others.
Severity Moderate Likelihood Possible Evidence B

Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the short version: your bladder medicine oxybutynin is partly cleared by a liver enzyme called CYP3A4. Bishop's Weed contains a compound (bergapten) that can slow that enzyme down. If the enzyme works slower, oxybutynin can hang around longer and build up in your blood, which may make its usual side effects stronger.

With oxybutynin, that often means more dry mouth, constipation, blurry vision, dizziness, or trouble urinating. Keep in mind this concern comes mostly from lab studies, so it's theoretical rather than proven in people. Still, since Bishop's Weed can also cause serious skin and eye reactions on its own, please don't combine these without checking with your pharmacist or doctor first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Malhotra S, Bailey DG, Paine MF, Watkins PB. Seville orange juice-felodipine interaction: comparison with dilute grapefruit juice and involvement of furocoumarins. Clin Pharmacol Ther 2001;69:14-23. PubMed

What These Ratings Mean

Every interaction above is graded three ways — here’s the key to each label.

Severity how clinically significant the interaction is
Major

Clinically significant. Avoid the combination, or use only under close professional supervision.

Moderate

Usually worth avoiding or managing — may need monitoring, a dose change, or timing apart.

Minor

Generally not serious. Be aware of it and mention it to your pharmacist.

Likelihood how strong the evidence is that the interaction actually happens in people
  • LikelyWell-controlled human studies have demonstrated the likely existence of this interaction.
  • ProbableInteraction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
  • PossibleInteraction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.
  • UnlikelyInteraction has been demonstrated in animal or in lab research but has been shown not to occur in humans.
Evidence the quality of the studies behind the rating (graded A–D)
  • AHigh-quality meta-analysis (quantitative systematic review).
  • BCase-control study.
  • CConsensus.
  • DAnecdotal evidence.

These ratings are for information only. Never start, stop, or otherwise change your therapy before speaking with your provider.

Keep it in perspective

Bishop's Weed Also Interacts With Other Medications

Bishop's Weed has 955 moderate known drug interactions in our database — the Oxybutynin one above is one of them. If you take anything else, check it against the full list below.

Moderate 955 No known interaction 1,875 (incl. Oxybutynin)
Taking anything else?

Check Another of Your Medications Against Bishop's Weed

Covers the 2,830 medications we’ve checked against Bishop's Weed. Pick one to open its full report.

From our Q&A

Questions About Bishop's Weed or Oxybutynin

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Bishop's Weed or Oxybutynin, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

Everything else you take

See Every Supplement That Interacts With Oxybutynin

This page covers Bishop's Weed only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Oxybutynin page lists 165 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Grapefruit (major), Henbane (major), Scopolia (major) and St. John's Wort (major).

By severity: 5 major · 116 moderate · 44 minor.

From our pharmacist’s overview on the Oxybutynin page

“Oxybutynin (Ditropan, Oxytrol, Gelnique) is an anticholinergic for overactive bladder, and its supplement interactions deserve genuine care rather than a quick skim. Most of the list comes down to drug levels: grapefruit juice can push oxybutynin higher and intensify its side effects, while St.”

Reviewed by 2 · Jul 18, 2026

Open the Oxybutynin interaction page

One more smart check

Taking Bishop's Weed as Part of a Dietary Supplement Product? Check It for Interactions

We hold 83 real supplement products containing Bishop's Weed, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Bishop's Weed. Your product may carry other ingredients that interact with Oxybutynin too, on top of Bishop's Weed — and those would not show on this page. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Bishop's Weed and Oxybutynin Sit Against Everything Else

Out of every supplement and medication people look up on HelloPharmacist, here is where these two land this week — and which way each has been moving.

Supplement Bishop's Weed
Top half

#550 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Oxybutynin
Steady interest

#2,108 of 2,830 medications looked up here in the last 7 days

29 days ago today

Position among everything looked up on this site, not a measure of how commonly either one is used or how important it is. A supplement can climb this list because of a news story. It counts every request to the page, automated ones included, and nothing here identifies anyone.

Supplement

About Bishop's Weed

What is Bishop's Weed?

Bishop's Weed
  • Vitiligo (loss of skin color)
  • Psoriasis
  • Digestive complaints
  • Asthma and breathing problems
  • Kidney stones
  • Diuretic (increasing urine)

Bishop's Weed (Ammi majus) is a flowering plant whose seeds contain natural light-sensitizing compounds called psoralens, which have been studied mainly for skin conditions like vitiligo and psoriasis when combined with light therapy. The plant is potentially toxic and can cause severe skin and eye reactions when exposed to sunlight, so it is not something to take on your own. If you are interested in psoralen-based treatments, work with a dermatologist rather than self-treating.

Read the full Bishop's Weed monograph & all interactions
Medication

About Oxybutynin

What Is Oxybutynin Used For?

Brand names: Ditropan, Ditropan XL, Oxybutynin, Oxytrol, Anturol, Gelnique

Oxybutynin treats overactive bladder — including the sudden urge to urinate, leaking before you can reach the bathroom (urge incontinence), and going too frequently. Extended-release tablets (Oxybutynin Chloride) and immediate-release tablets and oral solution (Oxybutynin Chloride) are used for these symptoms. Oxytrol is approved for overactive bladder in men; Oxytrol for Women is approved for overactive bladder in women aged 18 and older.

Extended-release tablets (Oxybutynin Chloride) are also approved for children 6 years and older who have bladder overactivity caused by a neurological condition, such as spina bifida. Immediate-release tablets and oral solution (Oxybutynin Chloride) are indicated for bladder instability symptoms — including urgency, frequency, urinary leakage, and painful urination — in patients with neurogenic bladder conditions.

See full Oxybutynin drug information
Keep checking

Other Drugs & Bishop's Weed

Browse every other medication we’ve checked against Bishop's Weed — both the ones with a known interaction and the ones without. Select any drug for the full detail.

0Major
955Moderate
0Minor
1,874No known interaction
955 Moderate 1,874 No interaction
Moderate

955 interactions

Showing 60 of 955 moderate interactions — see all 955 on the Bishop's Weed page.

No interaction 1,874 drugs checked — show the list

We also checked Bishop's Weed against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 1,874 medications checked with no known interaction — see the full Bishop's Weed list.

See the full Bishop's Weed interactions page
See every supplement checked against Oxybutynin, ranked by severity
Sources

Sources & How We Checked

Interaction details are evidence-graded and sourced from the Natural Medicines database. The medication overview comes from MedlinePlus.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

Keep exploring
Bishop's Weed monograph › Uses, safety, and every drug interaction in one place Oxybutynin supplement interactions › Every supplement checked against Oxybutynin, ranked by severity Oxybutynin drug information › The full plain-English guide to this medication Supplement interaction checker › Check any supplement or product against your medications Browse medications A–Z › Every drug we've checked against herbs & supplements Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking Bishop's Weed and Oxybutynin Together: Common Questions

Can you take Bishop's Weed with Oxybutynin?
There is a moderate interaction, so it may be acceptable with monitoring or timing changes — but check with your pharmacist first. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Bishop's Weed and Oxybutynin interaction?
We rate it Moderate. This combination may require monitoring, a dose adjustment, or separating the times you take each one. Consult your pharmacist before using them together.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Still Have a Question About Oxybutynin and Bishop's Weed?

Our pharmacists answer your medication & supplement questions — free.

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This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.