Drug & supplement interaction

Delta-9-tetrahydrocannabinol (thc) + Diclofenac epolamine

Diclofenac epolamine brand names: Flector, Licart.

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

Diclofenac epolamine falls into 2 drug categories that Delta-9-tetrahydrocannabinol (thc) can interact with; the most serious is rated moderate. Theoretically, THC might increase the risk of bleeding when used concomitantly with anticoagulant/antiplatelet drugs.

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

Delta-9-tetrahydrocannabinol (thc) and Diclofenac epolamine

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

Why Are There 2 Interactions?

Delta-9-tetrahydrocannabinol (thc) interacts with whole categories of medication. Diclofenac epolamine falls into 2 of those categories, so it can interact with Delta-9-tetrahydrocannabinol (thc) in 2 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).

Moderate

ANTICOAGULANT/ANTIPLATELET DRUGS

1 of 2

Why this applies to Diclofenac epolamine

Diclofenac epolamine falls under ANTICOAGULANT/ANTIPLATELET DRUGS — the group Delta-9-tetrahydrocannabinol (thc) interacts with.

Theoretically, THC might increase the risk of bleeding when used concomitantly with anticoagulant/antiplatelet drugs.
In vitro research shows that THC inhibits platelet aggregation.
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: Flector and Licart are diclofenac patches, an NSAID that you apply to the skin. NSAIDs like diclofenac can already make your blood a little slower to clot, which is why bruising, stomach upset, or, less often, bleeding can show up. THC, in lab studies only, appears to slow down platelets (the cells that help form clots). So in theory, pairing the two could nudge your bleeding risk up a bit.

I want to be honest about the strength of this: the evidence here comes only from test-tube and animal research, not real patients, so it's largely theoretical. With a topical patch, very little diclofenac reaches your whole body, so the concern is even smaller. Still, if you notice easy bruising, dark stools, or bleeding that won't stop, loop in your pharmacist or doctor.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Levy, R., Schurr, A., Nathan, I., Dvilanski, A., and Livne, A. Impairment of ADP-induced platelet aggregation by hashish components. Thromb.Haemost. 12-31-1976;36(3):634-640. DOI
  2. Formukong, E. A., Evans, A. T., and Evans, F. J. The inhibitory effects of cannabinoids, the active constituents of Cannabis sativa L. on human and rabbit platelet aggregation. J.Pharm.Pharmacol. 1989;41(10):705-709.
Minor

CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES

2 of 2

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

Theoretically, THC might increase the levels and adverse effects of CYP2C9 substrates.
In vitro research shows that THC moderately inhibits the CYP2C9-mediated 7-hydroxylation of S-warfarin in a concentration-dependent manner. In vitro research also shows that cannabis extracts containing THC modestly inhibit the CYP2C9 metabolism of tolbutamide; extracts providing the specific cannabinoids cannabidiol (CBD) or cannabigerol (CBG) alone had stronger inhibitory effects than extracts containing both THC and CBD. Theoretically, THC may inhibit the metabolism of other CYP2C9 substrates. Conversely, a crossover clinical study in healthy adults shows that oral THC does not inhibit CYP2C9.
Severity Minor Likelihood Unlikely Evidence D

Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans..

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Diclofenac, the active ingredient in Flector patches and Licart, is partly cleared by a liver enzyme called CYP2C9. THC may slow that enzyme down a little, which in theory could let diclofenac build up slightly and nudge up the usual NSAID side effects like stomach upset, heartburn, or fluid retention. That said, this is a very weak concern.

The signal here comes from lab (test-tube) studies, and a study in real people actually showed oral THC did not block CYP2C9. On top of that, Flector and Licart are topical patches, so very little drug reaches your bloodstream to begin with. I wouldn't lose sleep over this combo, but it's always smart to run your full list past your pharmacist or doctor.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Damkier P, Lassen D, Christensen MMH, Madsen KG, Hellfritzsch M, Pottegård A. Interaction between warfarin and cannabis. Basic Clin Pharmacol Toxicol. 2019;124(1):28-31. PubMed
  2. Treyer A, Reinhardt JK, Eigenmann DE, Oufir M, Hamburger M. Phytochemical comparison of medicinal cannabis extracts and study of their CYP-mediated interactions with coumarinic oral anticoagulants. Med Cannabis Cannabinoids. 2023;6(1):21-31. PubMed
  3. Bansal S, Zamarripa CA, Spindle TR, et al. Evaluation of Cytochrome P450-Mediated Cannabinoid-Drug Interactions in Healthy Adult Participants. Clin Pharmacol Ther 2023.

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

Delta-9-tetrahydrocannabinol (thc) Also Interacts With Other Medications

Delta-9-tetrahydrocannabinol (thc) has 761 moderate, 336 minor known drug interactions in our database — the Diclofenac epolamine one above is among them. If you take anything else, check it against the full list below.

Moderate 761 Minor 336 No known interaction 1,733 (incl. Diclofenac epolamine)
Taking anything else?

Check Another of Your Medications Against Delta-9-tetrahydrocannabinol (thc)

Covers the 2,830 medications we’ve checked against Delta-9-tetrahydrocannabinol (thc). Pick one to open its full report.

Everything else you take

See Every Supplement That Interacts With Diclofenac epolamine

This page covers Delta-9-tetrahydrocannabinol (thc) only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Diclofenac epolamine page lists 292 supplements it has a documented interaction with, worst first, each one explained.

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

By severity: 6 major · 259 moderate · 27 minor.

From our pharmacist’s overview on the Diclofenac epolamine page

“Even as a patch, diclofenac epolamine (Flector, Licart) is still an NSAID that reaches the bloodstream, and its 292 supplement interactions call for genuine care, six of them rated major. The bulk of the list, 202 ingredients, thins the blood or slows clotting, which stacks onto an NSAID's built-in bleeding risk.”

Reviewed by 2 · Jul 18, 2026

Open the Diclofenac epolamine interaction page

How much people look this up

Where Delta-9-tetrahydrocannabinol (thc) and Diclofenac epolamine 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 Delta-9-tetrahydrocannabinol (thc)
Top half

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

29 days ago today
Medication Diclofenac epolamine
Top 25%

#562 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 Delta-9-tetrahydrocannabinol (thc)

What is Delta-9-tetrahydrocannabinol (thc)?

Delta-9-tetrahydrocannabinol (thc)
  • Chronic or nerve pain
  • Nausea and vomiting from chemotherapy
  • Appetite loss and weight loss
  • Muscle spasticity
  • Sleep problems
  • Anxiety and stress

THC is the main mind-altering compound in cannabis and is best known for causing a 'high.' A prescription form (dronabinol) is approved for chemotherapy-related nausea and appetite loss, but for most other uses the evidence is mixed or limited, and THC can impair thinking and driving. It should be avoided in pregnancy and breastfeeding and used only with medical guidance.

Read the full Delta-9-tetrahydrocannabinol (thc) monograph & all interactions
Keep checking

Other Drugs & Delta-9-tetrahydrocannabinol (thc)

Browse every other medication we’ve checked against Delta-9-tetrahydrocannabinol (thc) — both the ones with a known interaction and the ones without. Select any drug for the full detail.

0Major
761Moderate
336Minor
1,732No known interaction
761 Moderate 336 Minor 1,732 No interaction
Moderate

761 interactions

Showing 60 of 761 moderate interactions — see all 761 on the Delta-9-tetrahydrocannabinol (thc) page.

Minor

336 interactions

Showing 60 of 336 minor interactions — see all 336 on the Delta-9-tetrahydrocannabinol (thc) page.

No interaction 1,732 drugs checked — show the list

We also checked Delta-9-tetrahydrocannabinol (thc) against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 1,732 medications checked with no known interaction — see the full Delta-9-tetrahydrocannabinol (thc) list.

See the full Delta-9-tetrahydrocannabinol (thc) interactions page
See every supplement checked against Diclofenac epolamine, 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
Delta-9-tetrahydrocannabinol (thc) monograph › Uses, safety, and every drug interaction in one place Diclofenac epolamine supplement interactions › Every supplement checked against Diclofenac epolamine, 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 Delta-9-tetrahydrocannabinol (thc) and Diclofenac epolamine Together: Common Questions

Can you take Delta-9-tetrahydrocannabinol (thc) with Diclofenac epolamine?
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 Delta-9-tetrahydrocannabinol (thc) and Diclofenac epolamine?
Diclofenac epolamine belongs to more than one drug category, and Delta-9-tetrahydrocannabinol (thc) 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 Delta-9-tetrahydrocannabinol (thc) and Diclofenac epolamine 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.