Drug & supplement interaction

Kava + Diclofenac Potassium

Diclofenac Potassium brand names: Voltaren Rapide, Cataflam, Cataflam IR, Voltarol Rapid, Cambia.

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

Diclofenac Potassium falls into 2 drug categories that Kava can interact with; the most serious is rated moderate. Theoretically, using kava with hepatotoxic drugs might increase the risk of liver damage.

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

Kava and Diclofenac Potassium

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

Why Are There 2 Interactions?

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

Moderate

HEPATOTOXIC DRUGS

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Why this applies to Diclofenac Potassium

Diclofenac Potassium falls under HEPATOTOXIC DRUGS — the group Kava interacts with.

Theoretically, using kava with hepatotoxic drugs might increase the risk of liver damage.
Kava has been linked with over 100 cases of hepatotoxicity. Most cases occur with excessive and prolonged use. There is some concern that kava can adversely affect the liver, especially when used in combination with hepatotoxic drugs.
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: both kava and diclofenac (Cataflam, Voltaren Rapide) can be hard on the liver. Diclofenac is a fairly common cause of liver enzyme changes, and kava has been linked to rare but serious liver injury, mostly with heavy or long-term use. The worry is that taking them together could add up and put more stress on your liver than either one alone.

To be fair, this is mostly a theoretical concern based on scattered case reports, not strong studies, so I don't want to alarm you. Still, watch for things like belly pain, unusual tiredness, dark urine, or yellowing of your skin or eyes, and let your doctor know. Please check with your pharmacist or doctor before combining these, especially if you already have any liver issues.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Escher M, Desmeules J, Giostra E, Mentha G. Hepatitis associated with Kava, a herbal remedy for anxiety. BMJ 2001;322:139.
  2. Russmann S, Lauterburg BH, Helbling A. Kava hepatotoxicity [letter]. Ann Intern Med 2001;135:68-9.
  3. Liver Toxicity With Kava. Pharmacist's Letter/Prescriber's Letter. January 2001.
  4. Consultation letter MLX 286: Proposals to prohibit the herbal ingredient Kava-Kava (Piper methysticum) in unlicensed medicines. Medicines Control Agency, United Kingdom, July 19, 2002.
  5. Li XZ, Ramzan I. Role of ethanol in kava hepatotoxicity. Phytother Res 2010;24:475-80. PubMed
  6. Chanwai, L. G. Kava toxicity. Emergency Medicine 2002;12:142-145.
Moderate

CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES

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Diclofenac Potassium also falls under CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES.

Theoretically, kava might increase levels of CYP2C9 substrates.
In vitro research shows that kava significantly inhibits CYP2C9 enzymes. This effect has not yet 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: your body relies on a liver enzyme called CYP2C9 to break down diclofenac. Lab studies (done in test tubes, not in real people yet) suggest kava can slow that enzyme down. If that happened in your body, diclofenac could clear more slowly and build up a bit, which might mean stronger effects and a higher chance of the usual NSAID side effects like stomach upset, heartburn, ulcers, or kidney strain.

I want to be honest about how shaky this is: it's only a theory from lab work, not something proven in humans, so I wouldn't lose sleep over it. The bigger concern with kava is that both it and diclofenac can be hard on the liver. Please check with your pharmacist or doctor before combining them.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Mathews JM, Etheridge AS, Black SR. Inhibition of human cytochrome P450 activities by kava extract and kavalactones. Drug Metab Dispos 2002;30:1153-7. PubMed
  2. Unger M, Frank A. Simultaneous determination of the inhibitory potency of herbal extracts on the activity of six major cytochrome P450 enzymes using liquid chromatography/mass spectrometry and automated online extraction. Rapid Commun Mass Spectrom 2004;1 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

Kava Also Interacts With Other Medications

Kava has 248 major, 580 moderate, 338 minor known drug interactions in our database — the Diclofenac Potassium one above is among them. If you take anything else, check it against the full list below.

Major 248 Moderate 580 Minor 338 No known interaction 1,664 (incl. Diclofenac Potassium)
Taking anything else?

Check Another of Your Medications Against Kava

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

From our Q&A

Questions About Kava or Diclofenac Potassium

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

This page covers Kava only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Diclofenac Potassium page lists 306 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Asarabacca (major), Beer (major), Danshen (major) and Piracetam (major).

Open the Diclofenac Potassium interaction page

One more smart check

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

We hold 403 real supplement products containing Kava, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Kava. Your product may carry other ingredients that interact with Diclofenac Potassium too, on top of Kava — 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 Kava and Diclofenac Potassium 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 Kava
Top 25%

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

29 days ago today
Medication Diclofenac Potassium
Top 25%

#698 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 Kava

What is Kava?

Kava
  • Anxiety and stress
  • Restlessness
  • Trouble sleeping
  • Relaxation in social or cultural settings
  • Menopausal symptoms

Kava is a Pacific Island plant traditionally used to promote relaxation and ease anxiety, and some studies suggest it may help mild anxiety. However, kava has been linked to rare but serious liver damage, so it should be used with caution, avoided by people with liver problems, and only used after talking with your pharmacist or doctor.

Read the full Kava monograph & all interactions
Medication

About Diclofenac

What Is Diclofenac Used For?

Brand names: Voltaren Rapide, Cataflam, Cataflam IR, Voltarol Rapid, Cambia

Diclofenac comes in many forms, and each one is approved for different uses. Which one you get depends on what you are treating.

  • Oral tablets: osteoarthritis, rheumatoid arthritis, and (delayed-release) ankylosing spondylitis, plus period pain and mild to moderate pain for the immediate-release potassium tablets.
  • Capsules: mild to moderate acute pain in adults.
  • Oral solution (powder for solution): acute treatment of migraine attacks in adults.
  • Topical gel and solution: osteoarthritis pain, mainly of the knees (and hands for the gel).
  • Skin patches (Flector, diclofenac epolamine): acute pain from minor strains, sprains and bruises.
See full Diclofenac drug information
Keep checking

Other Drugs & Kava

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

248Major
580Moderate
338Minor
1,663No known interaction
248 Major 580 Moderate 338 Minor 1,663 No interaction
Major

248 interactions

Showing 60 of 248 major interactions — see all 248 on the Kava page.

Moderate

580 interactions

Showing 60 of 580 moderate interactions — see all 580 on the Kava page.

Minor

338 interactions

Showing 60 of 338 minor interactions — see all 338 on the Kava page.

No interaction 1,663 drugs checked — show the list

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

Showing the 60 most looked-up of 1,663 medications checked with no known interaction — see the full Kava list.

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

Can you take Kava with Diclofenac Potassium?
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 Kava and Diclofenac Potassium?
Diclofenac Potassium belongs to more than one drug category, and Kava 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 Kava and Diclofenac Potassium 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 Diclofenac Potassium and Kava?

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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.