Drug & supplement interaction

Sage + Pseudoephedrine, Terfenadine

Pseudoephedrine, Terfenadine brand name: Teldafen.

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

Sage has a moderate interaction with Pseudoephedrine, Terfenadine. Theoretically, sage might increase levels of drugs transported by P-glycoprotein.

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

Sage and Pseudoephedrine, Terfenadine

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

Moderate

P-GLYCOPROTEIN SUBSTRATES

Why this applies to Pseudoephedrine, Terfenadine

Pseudoephedrine, Terfenadine falls under P-GLYCOPROTEIN SUBSTRATES — the group Sage interacts with.

Theoretically, sage might increase levels of drugs transported by P-glycoprotein.
In vitro research suggests that common sage (Salvia officinalis) can inhibit the multi-drug transporter protein, P-glycoprotein. 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 for your Teldafen (which pairs pseudoephedrine with terfenadine): lab studies hint that sage may block a transporter called P-glycoprotein, which helps move certain drugs out of your body. If that transporter slows down, a bit more of these medicines could stay in your system. With terfenadine that matters most, because higher levels were historically linked to dangerous heart rhythm changes. Pseudoephedrine could also feel a little stronger, meaning more jitteriness, a racing heart, or trouble sleeping.

That said, this is only seen in test tubes, not in people, so it's theoretical. Cooking with sage almost certainly won't matter. Concentrated sage extracts or oils are the real question, so check with your pharmacist or doctor before starting them.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Hellum, B. H. and Nilsen, O. G. In vitro inhibition of CYP3A4 metabolism and P-glycoprotein-mediated transport by trade herbal products. Basic Clin Pharmacol Toxicol. 2008;102(5):466-475.

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

Sage Also Interacts With Other Medications

Sage has 1,295 moderate known drug interactions in our database — the Pseudoephedrine, Terfenadine one above is one of them. If you take anything else, check it against the full list below.

Moderate 1,295 No known interaction 1,535 (incl. Pseudoephedrine, Terfenadine)
Taking anything else?

Check Another of Your Medications Against Sage

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

Everything else you take

See Every Supplement That Interacts With Pseudoephedrine, Terfenadine

This page covers Sage only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Pseudoephedrine, Terfenadine page lists 105 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Hellebore (major), Arsenic (major), Cesium (major) and Ephedra (major).

By severity: 10 major · 77 moderate · 18 minor.

From our pharmacist’s overview on the Pseudoephedrine, Terfenadine page

“Teldafen pairs the decongestant pseudoephedrine with terfenadine, an older antihistamine known for disturbing heart rhythm, so I read this list with real seriousness and you should too. The riskiest entries either stretch the heart's QT interval further, which is how dangerous arrhythmias begin (grapefruit in large amounts is one), or…”

Reviewed by 2 · Jul 18, 2026

Open the Pseudoephedrine, Terfenadine interaction page

One more smart check

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

We hold 718 real supplement products containing Sage, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Sage. Your product may carry other ingredients that interact with Pseudoephedrine, Terfenadine too, on top of Sage — 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 Sage and Pseudoephedrine, Terfenadine 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 Sage
Top 25%

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

29 days ago today
Medication Pseudoephedrine, Terfenadine
Top 25%

#644 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 Sage

What is Sage?

Sage
  • Sore throat and mouth irritation
  • Digestive upset
  • Excessive sweating
  • Memory and thinking
  • Menopause symptoms (hot flashes)
  • General antioxidant support

Sage is a common kitchen herb that is generally safe in food amounts and is traditionally used for sore throats, digestion, sweating, and memory. Some early research is encouraging for sore throat and menopausal hot flashes, but most uses are not well proven. Concentrated extracts and the essential oil should be used carefully because high doses contain a compound called thujone, which can be harmful.

Read the full Sage monograph & all interactions
Keep checking

Other Drugs & Sage

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

0Major
1,295Moderate
0Minor
1,534No known interaction
1,295 Moderate 1,534 No interaction
Moderate

1,295 interactions

Showing 60 of 1,295 moderate interactions — see all 1,295 on the Sage page.

No interaction 1,534 drugs checked — show the list

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

Showing the 60 most looked-up of 1,534 medications checked with no known interaction — see the full Sage list.

See the full Sage interactions page
See every supplement checked against Pseudoephedrine, Terfenadine, 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
Sage monograph › Uses, safety, and every drug interaction in one place Pseudoephedrine, Terfenadine supplement interactions › Every supplement checked against Pseudoephedrine, Terfenadine, 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 Sage and Pseudoephedrine, Terfenadine Together: Common Questions

Can you take Sage with Pseudoephedrine, Terfenadine?
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 Sage and Pseudoephedrine, Terfenadine 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.