Drug & supplement interaction

Chanca Piedra + Chlorpheniramine, Phenylephrine

Chlorpheniramine, Phenylephrine brand names: Histatab Plus, Ed A Hist, Rynatan, Dallergy JR.

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

Chanca Piedra has a moderate interaction with Chlorpheniramine, Phenylephrine. Theoretically, use of chanca piedra might increase the levels and clinical effects of CYP3A4 substrates.

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

Chanca Piedra and Chlorpheniramine, Phenylephrine

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

Moderate

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

Why this applies to Chlorpheniramine, Phenylephrine

Chlorpheniramine, Phenylephrine falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES — the group Chanca Piedra interacts with.

Theoretically, use of chanca piedra might increase the levels and clinical effects of CYP3A4 substrates.
In vitro research shows that chanca piedra extract inhibits CYP3A4. Theoretically, chanca piedra might increase the levels of CYP3A4 substrates. This interaction has not been reported in humans.
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 this allergy and decongestant combo. Chanca piedra has been shown, in lab dish studies only, to slow down a liver enzyme called CYP3A4. Since chlorpheniramine is partly cleared by that enzyme, the worry on paper is that the herb could let it build up a bit. That might mean more of chlorpheniramine's usual effects, like drowsiness, dry mouth, dizziness, or blurry vision. The phenylephrine piece can already bump up blood pressure and cause a racing or pounding heartbeat.

That said, this is theoretical and has never actually been reported in people. So I wouldn't lose sleep over it, but if you take both, please mention it to your pharmacist or doctor, especially if you notice extra grogginess.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Husain I, Abdulrahman B, Dale OR, et al. Interaction of Phyllanthus amarus extract and its lignans with human xenobiotic receptors, drug metabolizing enzymes and drug transporters. J Ethnopharmacol 2025;339:119142. 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

Chanca Piedra Also Interacts With Other Medications

Chanca Piedra has 870 moderate, 149 minor known drug interactions in our database — the Chlorpheniramine, Phenylephrine one above is one of them. If you take anything else, check it against the full list below.

Moderate 870 Minor 149 No known interaction 1,811 (incl. Chlorpheniramine, Phenylephrine)
Taking anything else?

Check Another of Your Medications Against Chanca Piedra

Covers the 2,830 medications we’ve checked against Chanca Piedra. Pick one to open its full report.

Everything else you take

See Every Supplement That Interacts With Chlorpheniramine, Phenylephrine

This page covers Chanca Piedra only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Chlorpheniramine, Phenylephrine 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, Phenylephrine page

“A medicine that stimulates the heart and dries the body doesn't leave much room for supplements pulling the same way, and that describes chlorpheniramine, phenylephrine (Histatab Plus, Ed A Hist, Rynatan) well. Dozens of stimulant herbs, everyday caffeine sources among them, add to the decongestant's strain on blood pressure and heart…”

Reviewed by 2 · Jul 18, 2026

Open the Chlorpheniramine, Phenylephrine interaction page

One more smart check

Taking Chanca Piedra as Part of a Dietary Supplement Product? Check It for Interactions

We hold 355 real supplement products containing Chanca Piedra, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Chanca Piedra. Your product may carry other ingredients that interact with Chlorpheniramine, Phenylephrine too, on top of Chanca Piedra — 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 Chanca Piedra and Chlorpheniramine, Phenylephrine 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 Chanca Piedra
Top half

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

29 days ago today
Medication Chlorpheniramine, Phenylephrine
Top half

#1,278 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 Chanca Piedra

What is Chanca Piedra?

Chanca Piedra
  • Kidney stones
  • Gallstones
  • Liver support
  • Urinary tract health
  • Digestive complaints

Chanca piedra is a tropical herb traditionally used as a 'stone breaker' for kidney and gallstones, and for liver and urinary health. Human evidence for these uses is limited and mostly small or preliminary, so it should not replace proven treatments. Talk with your pharmacist or doctor before using it, especially if you have a medical condition or take medications.

Read the full Chanca Piedra monograph & all interactions
Keep checking

Other Drugs & Chanca Piedra

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

0Major
870Moderate
149Minor
1,810No known interaction
870 Moderate 149 Minor 1,810 No interaction
Moderate

870 interactions

Showing 60 of 870 moderate interactions — see all 870 on the Chanca Piedra page.

Minor

149 interactions

Showing 60 of 149 minor interactions — see all 149 on the Chanca Piedra page.

No interaction 1,810 drugs checked — show the list

We also checked Chanca Piedra against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 1,810 medications checked with no known interaction — see the full Chanca Piedra list.

See the full Chanca Piedra interactions page
See every supplement checked against Chlorpheniramine, Phenylephrine, 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
Chanca Piedra monograph › Uses, safety, and every drug interaction in one place Chlorpheniramine, Phenylephrine supplement interactions › Every supplement checked against Chlorpheniramine, Phenylephrine, 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 Chanca Piedra and Chlorpheniramine, Phenylephrine Together: Common Questions

Can you take Chanca Piedra with Chlorpheniramine, Phenylephrine?
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 Chanca Piedra and Chlorpheniramine, Phenylephrine 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 Chlorpheniramine, Phenylephrine and Chanca Piedra?

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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.