Drug & supplement interaction

Uva Ursi + Formoterol

Formoterol brand names: Foradil Aerolizer, Atimos Modulite, Oxis Turbohaler, Perforomist, Foradil Certihaler.

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

Uva Ursi has a moderate interaction with Formoterol. Theoretically, uva ursi may decrease the metabolism of CYP2C19 substrates.

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

Uva Ursi and Formoterol

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

Moderate

CYTOCHROME P450 2C19 (CYP2C19) SUBSTRATES

Why this applies to Formoterol

Formoterol falls under CYTOCHROME P450 2C19 (CYP2C19) SUBSTRATES — the group Uva Ursi interacts with.

Theoretically, uva ursi may decrease the metabolism of CYP2C19 substrates.
In vitro, uva ursi appears to inhibit cytochrome CYP2C19. This effect 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 short version on pairing uva ursi with your formoterol inhaler: this is a very theoretical concern, not something seen in real people. In a lab dish, uva ursi seemed to slow down an enzyme called CYP2C19. The idea is that if that enzyme clears formoterol more slowly, a bit more could linger in your system, possibly nudging up side effects like a fast or pounding heartbeat, shakiness, headache, or feeling jittery.

That said, this was only an in vitro (test tube) finding, never confirmed in humans, so I wouldn't lose sleep over it. Formoterol is a working drug, not a prodrug, so its benefit shouldn't drop. Still, since uva ursi is best used only short-term, it's worth a quick chat with your pharmacist or doctor before combining them.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Chauhan B, Yu C, Krantis A, et al. In vitro activity of uva-ursi against cytochrome P450 isoenzymes and P-glycoprotein. Can J Physiol Pharmacol. 2007;85(11):1099-107.

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

Uva Ursi Also Interacts With Other Medications

Uva Ursi has 739 moderate, 63 minor known drug interactions in our database — the Formoterol one above is one of them. If you take anything else, check it against the full list below.

Moderate 739 Minor 63 No known interaction 2,028 (incl. Formoterol)
Taking anything else?

Check Another of Your Medications Against Uva Ursi

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

Everything else you take

See Every Supplement That Interacts With Formoterol

This page covers Uva Ursi only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Formoterol page lists 103 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: 1,3-dmaa (moderate), Acacia Rigidula (moderate), Active Hexose Correlated Compound (ahcc) (moderate), Adrafinil (moderate) and African Wild Potato (moderate).

By severity: 84 moderate · 19 minor.

From our pharmacist’s overview on the Formoterol page

“Formoterol (Foradil, Perforomist) is the long-acting half of many asthma and COPD inhalers, keeping airways open for hours, and its supplement list is calmer than its length suggests. None of the 103 ingredients on file is rated major.”

Reviewed by 2 · Jul 18, 2026

Open the Formoterol interaction page

One more smart check

Taking Uva Ursi as Part of a Dietary Supplement Product? Check It for Interactions

We hold 1,423 real supplement products containing Uva Ursi, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Uva Ursi. Your product may carry other ingredients that interact with Formoterol too, on top of Uva Ursi — 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 Uva Ursi and Formoterol 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 Uva Ursi
Top 25%

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

29 days ago today
Medication Formoterol
Top half

#1,385 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 Uva Ursi

What is Uva Ursi?

Uva Ursi
  • Urinary tract infections
  • Urinary discomfort
  • Mild diuretic
  • Kidney stones
  • Skin conditions

Uva ursi is a traditional herb used mainly for urinary tract infections, and its leaves contain a compound called arbutin that may have antimicrobial effects in the urine. Evidence in people is limited, and because high doses or long-term use may be harmful to the liver and could be toxic, it should only be used short-term and with guidance from a healthcare professional. Avoid it during pregnancy and breastfeeding.

Read the full Uva Ursi monograph & all interactions
Medication

About Formoterol Oral Inhalation

What Is Formoterol Oral Inhalation Used For?

Brand names: Foradil Aerolizer, Atimos Modulite, Oxis Turbohaler, Perforomist, Foradil Certihaler

Formoterol fumarate inhalation solution is used for the long-term maintenance treatment of airway narrowing (bronchoconstriction) in adults with COPD, including chronic bronchitis and emphysema. It is taken twice daily — morning and evening — as a regular, ongoing treatment.

Important limits: This medication is not for relieving sudden COPD flare-ups or breathlessness in the moment, and it is not approved to treat asthma. A separate short-acting inhaler should always be on hand for sudden symptoms.

See full Formoterol Oral Inhalation drug information
Keep checking

Other Drugs & Uva Ursi

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

0Major
739Moderate
63Minor
2,027No known interaction
739 Moderate 63 Minor 2,027 No interaction
Moderate

739 interactions

Showing 60 of 739 moderate interactions — see all 739 on the Uva Ursi page.

Minor

63 interactions

Showing 60 of 63 minor interactions — see all 63 on the Uva Ursi page.

No interaction 2,027 drugs checked — show the list

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

Showing the 60 most looked-up of 2,027 medications checked with no known interaction — see the full Uva Ursi list.

See the full Uva Ursi interactions page
See every supplement checked against Formoterol, 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
Uva Ursi monograph › Uses, safety, and every drug interaction in one place Formoterol supplement interactions › Every supplement checked against Formoterol, ranked by severity Formoterol Oral Inhalation 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 Uva Ursi and Formoterol Together: Common Questions

Can you take Uva Ursi with Formoterol?
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 Uva Ursi and Formoterol 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 Formoterol and Uva Ursi?

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.