Drug & supplement interaction

Ipriflavone + Montelukast Sodium

Montelukast Sodium brand name: Singulair.

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

Ipriflavone has a moderate interaction with Montelukast Sodium. Ipriflavone is thought to competitively inhibit cytochrome P450 2C9 (CYP2C9).

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

Ipriflavone and Montelukast Sodium

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

Moderate

CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES

Why this applies to Montelukast Sodium

Montelukast Sodium falls under CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES — the group Ipriflavone interacts with.

Ipriflavone is thought to competitively inhibit cytochrome P450 2C9 (CYP2C9). Theoretically, concurrent use of ipriflavone and drugs metabolized by these enzymes might result in decreased drug elimination, increased serum levels, and potential toxicity. Some drugs metabolized by CYP2C9 include amitriptyline (Elavil), diazepam (Valium), estradiol (Estrace), tacrine (Cognex), verapamil (Calan), warfarin (Coumadin), zileuton (Zyflo), and others.
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 simple version. Your body clears Singulair (montelukast) partly using a liver enzyme called CYP2C9. Ipriflavone may slow that enzyme down, so in theory montelukast could hang around a little longer and build up. Montelukast is not a prodrug, so more of it in your system would mean a stronger drug effect and a slightly higher chance of side effects like headache, stomachache, or feeling more tired.

The good news: this concern comes only from lab and test-tube research, not from real people, so we honestly don't know if it matters day to day. Montelukast also has a wide safety margin. Still, I'd mention the ipriflavone to your pharmacist or doctor before combining them, just to be safe.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Monostory K, Vereczkey L, Levai F, et al. Ipriflavone as an inhibitor of human cytochrome P450 enzymes. Br J Pharmacol 1998;123:605-10. 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

Ipriflavone Also Interacts With Other Medications

Ipriflavone has 390 moderate known drug interactions in our database — the Montelukast Sodium one above is one of them. If you take anything else, check it against the full list below.

Moderate 390 No known interaction 2,440 (incl. Montelukast Sodium)
Taking anything else?

Check Another of Your Medications Against Ipriflavone

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

From our Q&A

Questions About Ipriflavone or Montelukast Sodium

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Ipriflavone or Montelukast Sodium, 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 Montelukast Sodium

This page covers Ipriflavone only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Montelukast Sodium page lists 81 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Adrafinil (moderate), African Wild Potato (moderate), Bacopa (moderate) and Berberine (moderate).

By severity: 1 major · 56 moderate · 24 minor.

From our pharmacist’s overview on the Montelukast Sodium page

“If you rely on montelukast (Singulair) for asthma or allergies, this list deserves genuine attention. The one major-rated concern is activated charcoal, which can soak up the medicine in your gut before it absorbs, leaving you with a weaker dose just when your airways need a steady one.”

Reviewed by 2 · Jul 18, 2026

Open the Montelukast Sodium interaction page

One more smart check

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

We hold 204 real supplement products containing Ipriflavone, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Ipriflavone. Your product may carry other ingredients that interact with Montelukast Sodium too, on top of Ipriflavone — 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 Ipriflavone and Montelukast Sodium 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 Ipriflavone
Top half

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

29 days ago today
Medication Montelukast Sodium
Top 5%

#138 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 Ipriflavone

What is Ipriflavone?

Ipriflavone
  • Bone density and osteoporosis
  • Postmenopausal bone loss
  • Athletic performance
  • Tinnitus related to bone disorders

Ipriflavone is a synthetic isoflavone studied mainly for bone health and osteoporosis, but high-quality research has not shown that it reliably prevents fractures or builds strong bone. Because it can lower white blood cell counts in some people and its long-term safety is not well established, talk with your pharmacist or doctor before using it.

Read the full Ipriflavone monograph & all interactions
Medication

About Montelukast

What Is Montelukast Used For?

Brand name: Singulair

Montelukast is used for the long-term prevention and treatment of asthma in children and adults, and for preventing breathing problems triggered by exercise (exercise-induced bronchoconstriction). It is also used to relieve symptoms of seasonal allergic rhinitis (hay fever) and perennial allergic rhinitis (year-round nasal allergies). The age ranges covered depend on the specific product form — tablets, chewable tablets, and oral granules are each approved for different age groups.

For allergic rhinitis, montelukast should be reserved for people who haven't responded well to other treatments, because its potential mental health risks may outweigh the benefits when nasal allergy symptoms are mild and other options work. It is not a rescue treatment for sudden asthma attacks — always keep a fast-acting inhaler on hand.

See full Montelukast drug information
Keep checking

Other Drugs & Ipriflavone

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

0Major
390Moderate
0Minor
2,439No known interaction
390 Moderate 2,439 No interaction
Moderate

390 interactions

Showing 60 of 390 moderate interactions — see all 390 on the Ipriflavone page.

No interaction 2,439 drugs checked — show the list

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

Showing the 60 most looked-up of 2,439 medications checked with no known interaction — see the full Ipriflavone list.

See the full Ipriflavone interactions page
See every supplement checked against Montelukast Sodium, 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
Ipriflavone monograph › Uses, safety, and every drug interaction in one place Montelukast Sodium supplement interactions › Every supplement checked against Montelukast Sodium, ranked by severity Montelukast 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 Ipriflavone and Montelukast Sodium Together: Common Questions

Can you take Ipriflavone with Montelukast Sodium?
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 Ipriflavone and Montelukast Sodium 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 Montelukast Sodium and Ipriflavone?

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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.