Drug & supplement interaction

Bishop's Weed + Nifedipine

Nifedipine brand names: Procardia XL, Adalat PA, Adalat, Nifedin, Nifed PA, and others.

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

Nifedipine falls into 2 drug categories that Bishop's Weed can interact with; the most serious is rated moderate. Bishop's weed constituents seem to cause photosensitivity.

Read the full interaction report
SeverityModerate
LikelihoodPossible
Interactions2
EvidenceD
What do Severity, Likelihood & Evidence mean?
Know someone taking this? Share
Facebook Post Reddit Email
On this page
Interaction report

Bishop's Weed and Nifedipine

These two interact in 2 distinct ways. Each one is explained separately below.

Why Are There 2 Interactions?

Bishop's Weed interacts with whole categories of medication. Nifedipine falls into 2 of those categories, so it can interact with Bishop's Weed in 2 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).

Moderate

PHOTOSENSITIZING DRUGS

1 of 2

Why this applies to Nifedipine

Nifedipine falls under PHOTOSENSITIZING DRUGS — the group Bishop's Weed interacts with.

Bishop's weed constituents seem to cause photosensitivity. Theoretically, concomitant use of bishop's weed with photosensitizing drugs might result in increased photosensitivity.
Some drugs that cause photosensitivity include amitriptyline (Elavil), quinolones (Ciprofloxacin, others), sulfa drugs (Septra, Bactrim, others), and tetracycline.
Severity Moderate Likelihood Possible Evidence D

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 thing about pairing Bishop's Weed with your nifedipine: the concern isn't about how your body breaks down the medicine or how well it controls your blood pressure or chest pain. Instead, it's about your skin. Bishop's Weed contains psoralens, natural compounds that make your skin much more sensitive to sunlight. Nifedipine itself can also occasionally make skin more sun-sensitive, so using both together could, in theory, add up to a stronger reaction.

In plain terms, that means you might sunburn faster or break out in a rash after being outside. I'll be honest, this is based on weak, anecdotal evidence, so it's more a caution than a firm warning. If you do use both, be smart with sunscreen and cover up, and check with your pharmacist or doctor first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Ossenkoppele PM, van der Sluis WG, van Vloten WA. [Phototoxic dermatitis following the use of Ammi majus fruit for vitiligo]. Ned Tijdschr Geneeskd 1991;135:478-80.
  2. Dr. Duke's Phytochemical and Ethnobotanical Databases. Available at: http://www.ars-grin.gov/duke/.
Moderate

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

2 of 2

Nifedipine also falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES.

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 gist for nifedipine: your liver clears this blood pressure medicine using an enzyme called CYP3A4. Bishop's Weed contains a compound (bergapten) that may slow that same enzyme down. If the enzyme works slower, nifedipine can build up in your blood and hit harder than expected. That could mean too much of its usual effects, like dizziness, flushing, headache, swollen ankles, or blood pressure dropping too low.

I'll be honest, this is mostly theoretical, based on lab studies rather than real-world cases, so I don't want to alarm you. Still, Bishop's Weed isn't something to take on your own anyway. If you're considering it, please check with your pharmacist or doctor first so they can keep an eye on your blood pressure.

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 953 moderate known drug interactions in our database — the Nifedipine one above is among them. If you take anything else, check it against the full list below.

Moderate 953 No known interaction 1,877 (incl. Nifedipine)
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 Nifedipine

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 Nifedipine, 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 Nifedipine

This page covers Bishop's Weed only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Nifedipine page lists 273 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Hellebore (major), American Mistletoe (major), Beer (major) and Coca (major).

By severity: 11 major · 223 moderate · 39 minor.

From our pharmacist’s overview on the Nifedipine page

“Nifedipine (Procardia XL, Adalat) relaxes blood vessels to lower blood pressure and ease chest pain, and I would handle this list with real care, since 11 of its 273 entries carry a major rating. Grapefruit is the one to know cold.”

Reviewed by 2 · Jul 18, 2026

Open the Nifedipine 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 Nifedipine 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 Nifedipine 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 25%

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

29 days ago today
Medication Nifedipine
Top half

#855 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 Nifedipine

What Is Nifedipine Used For?

Brand names: Procardia XL, Adalat PA, Adalat, Nifedin, Nifed PA, Nifed, Procardia, Adalat XL, Adalat CC, Adalat LA, Adalat Retard, Adipine MR, Adipine XL, Cardilate MR, Coracten SR, Coracten XL, Fortipine LA 40, Hypolar Retard 20, Nifedipress MR, Nifopress Retard, Tensipine MR

Nifedipine treats high blood pressure (hypertension), chronic stable angina (chest pain brought on by physical effort), and vasospastic angina (chest pain caused by spasm of the coronary arteries, sometimes called Prinzmetal's angina). Lowering blood pressure with nifedipine helps reduce the risk of strokes and heart attacks.

The capsule form is approved for vasospastic angina and chronic stable angina only — it is not approved for high blood pressure. The extended-release tablet (including Procardia) covers all three uses: vasospastic angina, chronic stable angina, and high blood pressure.

See full Nifedipine 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
953Moderate
0Minor
1,876No known interaction
953 Moderate 1,876 No interaction
Moderate

953 interactions

Showing 60 of 953 moderate interactions — see all 953 on the Bishop's Weed page.

No interaction 1,876 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 1,876 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 Nifedipine, 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 Nifedipine supplement interactions › Every supplement checked against Nifedipine, ranked by severity Nifedipine 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 Nifedipine Together: Common Questions

Can you take Bishop's Weed with Nifedipine?
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.
Why are there 2 interactions listed for Bishop's Weed and Nifedipine?
Nifedipine belongs to more than one drug category, and Bishop's Weed interacts with each of those categories a little differently. We list every one so nothing is missed — your overall risk is driven by the most serious of them.
How serious is the Bishop's Weed and Nifedipine 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 Nifedipine and Bishop's Weed?

Our pharmacists answer your medication & supplement questions — free.

Ask a pharmacist

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.