Drug & supplement interaction

Puravive + Fosphenytoin

Fosphenytoin brand name: Cerebyx.

Moderate Interaction
Medically reviewed by · Updated February 2024
The bottom line Moderate

Fosphenytoin falls into 2 drug categories that Puravive can interact with; the most serious is rated moderate. Puravive contains quercetin, which has been shown in studies to mildly inhibit the CYP2C9 metabolizing enzyme.

Read the full interaction report
SeverityModerate
LikelihoodPossible
Interactions2
EvidenceC
What do Severity, Likelihood & Evidence mean?
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Interaction report

Puravive and Fosphenytoin

These two interact in 2 distinct ways. Each one is explained separately below.

Why Are There 2 Interactions?

Puravive interacts with whole categories of medication. Fosphenytoin falls into 2 of those categories, so it can interact with Puravive in 2 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).

Moderate

Cytochrome P450 2C9 (Cyp2C9) Substrates

1 of 2

Why this applies to Fosphenytoin

Fosphenytoin falls under Cytochrome P450 2C9 (Cyp2C9) Substrates — the group Puravive interacts with.

Puravive contains quercetin, which has been shown in studies to mildly inhibit the CYP2C9 metabolizing enzyme. This inhibition could potentially increase the risk of side effects from drugs. A small clinical trial with healthy volunteers found that taking 500 mg of quercetin twice daily for 10 days before using diclofenac, a drug metabolized by CYP2C9, increased diclofenac plasma levels by 75% and extended its half-life by 32.5% (source: https://pubmed.ncbi.nlm.nih.gov/29168292/). Combining quercetin with drugs metabolized by CYP2C9 could increase the risk of side effects, so caution is advised.
Severity Moderate Likelihood Possible Evidence C

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 thing to know about Puravive and fosphenytoin. Once fosphenytoin is given, your body quickly turns it into phenytoin, and phenytoin is cleared mainly by an enzyme called CYP2C9. Puravive contains quercetin, which can mildly slow that same enzyme down. If phenytoin clears more slowly, its levels can creep up, and phenytoin is a drug where the safe range is narrow. Even a small bump can tip you into side effects like dizziness, unsteady walking, slurred speech, double vision, or drowsiness.

That said, this is based on limited evidence (a small quercetin study with a different drug), so it's a possible concern, not a sure one. Since fosphenytoin is usually given in a hospital and monitored, please mention any Puravive use to your care team rather than starting or stopping anything yourself.

Contact Dr. Brian directly if you have additional questions on this interaction
Moderate

Qt Interval-Prolonging Drugs

2 of 2

Fosphenytoin also falls under Qt Interval-Prolonging Drugs.

Puravive contains Panax ginseng. Panax ginseng is thought to have an additive effect with drugs that prolong the QT interval, potentially increasing the risk of ventricular arrhythmias. However, research findings on this matter are conflicting. Clinical studies indicate that short-term use of Panax ginseng can increase the QT interval (source: https://pubmed.ncbi.nlm.nih.gov/27240158/). However, no changes in the QT interval have been observed with prolonged use (source: https://pubmed.ncbi.nlm.nih.gov/11978148/).
Severity Moderate Likelihood Possible Evidence C

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 thing to know about pairing Puravive with fosphenytoin (Cerebyx). Puravive contains Panax ginseng, and some short-term studies suggest ginseng can slightly stretch out the QT interval, which is a measure of your heart's electrical timing. Fosphenytoin can also affect heart rhythm, especially when it's given quickly by IV. Stacking two things that both nudge the QT in the same direction could, in theory, raise the small chance of an irregular heartbeat.

I want to be straight with you though: the evidence here is mixed and fairly weak, and longer-term ginseng use hasn't shown the same effect. Fosphenytoin is usually given in a hospital where your heart is monitored anyway. Still, please mention any supplement you take to your doctor or pharmacist before treatment, so they have the full picture.

Contact Dr. Brian directly if you have additional questions on this interaction

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

Puravive Also Interacts With Other Medications

Puravive has 356 moderate, 881 minor known drug interactions in our database — the Fosphenytoin one above is among them. If you take anything else, check it against the full list below.

Moderate 356 Minor 881 No known interaction 1,593 (incl. Fosphenytoin)
Taking anything else?

Check Another of Your Medications Against Puravive

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

From our Q&A

Questions About Puravive or Fosphenytoin

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

This page covers Puravive only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Fosphenytoin page lists 205 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: 1,4-butanediol (major), American Hellebore (major), Arsenic (major), Beer (major) and Cesium (major).

By severity: 14 major · 172 moderate · 19 minor.

From our pharmacist’s overview on the Fosphenytoin page

“St. John's wort is the entry I would flag first with fosphenytoin (Cerebyx).”

Reviewed by 2 · Jul 18, 2026

Open the Fosphenytoin interaction page

How much people look this up

Where Puravive and Fosphenytoin 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 Puravive
Top half

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

29 days ago today
Medication Fosphenytoin
Top half

#852 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 Puravive

What is Puravive?

Puravive
  • Weight management
  • Metabolism support
  • Energy levels
  • General wellness
  • Stress and brain health

Puravive is a branded, multi-ingredient capsule marketed mainly for weight loss by claiming to boost brown fat activity, but there is no published, independent clinical research showing the product itself works for this purpose. Some individual ingredients have been studied in laboratory or small human studies, but those results do not prove the finished blend is safe or effective. Talk to a pharmacist or doctor before trying it, especially if you have health conditions or take medications.

Read the full Puravive monograph & all interactions
Medication

About Fosphenytoin Injection

What Is Fosphenytoin Injection Used For?

Brand name: Cerebyx

Fosphenytoin injection is used to treat generalized tonic-clonic status epilepticus (a prolonged, life-threatening seizure emergency) and to prevent or treat seizures that occur during or after brain surgery. It is given by intravenous (IV) or intramuscular (IM) injection in a hospital or clinical setting.

It can also be used short-term as a substitute for oral phenytoin when a patient cannot take medicine by mouth. This use is temporary — as soon as oral phenytoin is possible again, it should replace the injection.

See full Fosphenytoin Injection drug information
Keep checking

Other Drugs & Puravive

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

0Major
356Moderate
881Minor
1,592No known interaction
356 Moderate 881 Minor 1,592 No interaction
Moderate

356 interactions

Showing 60 of 356 moderate interactions — see all 356 on the Puravive page.

Minor

881 interactions

Showing 60 of 881 minor interactions — see all 881 on the Puravive page.

No interaction 1,592 drugs checked — show the list

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

Showing the 60 most looked-up of 1,592 medications checked with no known interaction — see the full Puravive list.

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

Can you take Puravive with Fosphenytoin?
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 Puravive and Fosphenytoin?
Fosphenytoin belongs to more than one drug category, and Puravive 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 Puravive and Fosphenytoin 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 Fosphenytoin and Puravive?

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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.