Drug & supplement interaction

Bishop's Weed + Chlorpheniramine Tannate, Phenylephrine Tannate

Chlorpheniramine Tannate, Phenylephrine Tannate brand name: Ricobid.

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

Chlorpheniramine Tannate, Phenylephrine Tannate 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?
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Interaction report

Bishop's Weed and Chlorpheniramine Tannate, Phenylephrine Tannate

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. Chlorpheniramine Tannate, Phenylephrine Tannate 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 Chlorpheniramine Tannate, Phenylephrine Tannate

Chlorpheniramine Tannate, Phenylephrine Tannate 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 gist for your Ricobid (chlorpheniramine and phenylephrine). This is an antihistamine and decongestant combo for cold and allergy symptoms, and it isn't broken down or activated by the same pathways the psoralens in Bishop's Weed act on. The concern here isn't about one changing the other's blood levels. Instead, it's about overlapping skin effects.

Bishop's Weed contains psoralens that make your skin more sensitive to sunlight, and some sources note that medicines in this category may add to that. Honestly, this is based on weak, anecdotal evidence and is largely theoretical. Still, if you're using both, take sensible sun precautions (sunscreen, covering up) and watch for easy sunburn or rashes. Check with your pharmacist or doctor before combining them.

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

Chlorpheniramine Tannate, Phenylephrine Tannate 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 Ricobid, which pairs an antihistamine (chlorpheniramine) with a decongestant (phenylephrine). The psoralen compounds in bishop's weed, especially bergapten, can slow down a liver enzyme called CYP3A4 that helps break down many medicines. Chlorpheniramine is partly handled by this enzyme, so in theory its levels could drift a little higher and linger longer.

If that happened, you might notice more of the usual chlorpheniramine effects: drowsiness, dry mouth, blurred vision, or feeling foggy. Keep in mind this is mostly theoretical, based on lab studies rather than people, so the real-world risk is probably small. Still, since bishop's weed is potent and not meant for self-use, please run any combination past 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 953 moderate known drug interactions in our database — the Chlorpheniramine Tannate, Phenylephrine Tannate 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. Chlorpheniramine Tannate, Phenylephrine Tannate)
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.

Everything else you take

See Every Supplement That Interacts With Chlorpheniramine Tannate, Phenylephrine Tannate

This page covers Bishop's Weed only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Chlorpheniramine Tannate, Phenylephrine Tannate page lists 229 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Ephedra (major), Grapefruit (major), Henbane (major) and Lithium (major).

By severity: 10 major · 175 moderate · 44 minor.

From our pharmacist’s overview on the Chlorpheniramine Tannate, Phenylephrine Tannate page

“Ricobid pairs chlorpheniramine, an antihistamine, with phenylephrine, a decongestant, and 229 supplement and herbal ingredients interact with it, ten of them at major severity. That count earns real caution, not a shrug.”

Reviewed by 2 · Jul 18, 2026

Open the Chlorpheniramine Tannate, Phenylephrine Tannate 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 Chlorpheniramine Tannate, Phenylephrine Tannate 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 Chlorpheniramine Tannate, Phenylephrine Tannate 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

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

29 days ago today
Medication Chlorpheniramine Tannate, Phenylephrine Tannate
Top 10%

#280 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
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 Chlorpheniramine Tannate, Phenylephrine Tannate, 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 Chlorpheniramine Tannate, Phenylephrine Tannate supplement interactions › Every supplement checked against Chlorpheniramine Tannate, Phenylephrine Tannate, ranked by severity 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 Chlorpheniramine Tannate, Phenylephrine Tannate Together: Common Questions

Can you take Bishop's Weed with Chlorpheniramine Tannate, Phenylephrine Tannate?
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 Chlorpheniramine Tannate, Phenylephrine Tannate?
Chlorpheniramine Tannate, Phenylephrine Tannate 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 Chlorpheniramine Tannate, Phenylephrine Tannate 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

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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.