Drug & supplement interaction

Cannabis + Voriconazole

Voriconazole brand name: Vfend.

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

Voriconazole falls into 5 drug categories that Cannabis can interact with; the most serious is rated moderate. Theoretically, drugs that are CYP2C9 inhibitors might increase the adverse effects of cannabis.

Read the full interaction report
SeverityModerate
LikelihoodPossible
Interactions5
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Cannabis and Voriconazole

These two interact in 5 distinct ways. Each one is explained separately below.

Why Are There 5 Interactions?

Cannabis interacts with whole categories of medication. Voriconazole falls into 5 of those categories, so it can interact with Cannabis in 5 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) INHIBITORS

1 of 5

Why this applies to Voriconazole

Voriconazole falls under CYTOCHROME P450 2C9 (CYP2C9) INHIBITORS — the group Cannabis interacts with.

Theoretically, drugs that are CYP2C9 inhibitors might increase the adverse effects of cannabis.
Delta-9-tetrahydrocannabinol (THC), an active constituent of cannabis, is a substrate of CYP2C9 enzymes.
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 key thing to know: in this pairing, it's the cannabis that gets affected, not your voriconazole. Voriconazole blocks a liver enzyme called CYP2C9, and that same enzyme helps break down THC, the part of cannabis that makes you feel high. So while you're on voriconazole, THC may clear out of your body more slowly and build up.

In plain terms, the cannabis could hit harder and last longer than you expect, meaning more drowsiness, dizziness, a racing heart, confusion, or feeling more impaired than usual. Your voriconazole should keep working normally to fight the infection. One honest caveat: this is a theoretical concern based on how the enzyme works, not strong human studies. Still, it's worth a quick chat with your doctor or pharmacist before combining them.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Product information for Marinol. AbbVie. North Chicago, IL 60064. August 2017. Available at: https://www.accessdata.fda.gov/drugsatfda_docs/label/2017/018651s029lbl.pdf.
Moderate

CYTOCHROME P450 3A4 (CYP3A4) INHIBITORS

2 of 5

Voriconazole also falls under CYTOCHROME P450 3A4 (CYP3A4) INHIBITORS.

Theoretically, CYP3A4 inhibitors might increase the levels and adverse effects of cannabis.
Delta-9-tetrahydrocannabinol (THC), an active constituent of cannabis, is a substrate of CYP3A4 enzymes.
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 thing to know if you use cannabis while taking voriconazole (Vfend): voriconazole is a strong blocker of a liver enzyme called CYP3A4, and your body uses that same enzyme to break down THC, the part of cannabis that gets you high. So with voriconazole slowing that breakdown, THC can hang around longer and build up. In plain terms, the cannabis itself may hit harder and last longer, meaning more drowsiness, dizziness, a racing heart, anxiety, or feeling more impaired than usual.

Just to be clear, this is a theoretical concern based on how the drugs work, not something proven in big studies, so don't panic. Voriconazole's own effect on your infection shouldn't change. Still, it's worth a quick chat with your doctor or pharmacist before mixing the two.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Product information for Marinol. AbbVie. North Chicago, IL 60064. August 2017. Available at: https://www.accessdata.fda.gov/drugsatfda_docs/label/2017/018651s029lbl.pdf.
Moderate

CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES

3 of 5

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

Theoretically, cannabis might increase the levels and adverse effects of CYP2C9 substrates.
In vitro research shows that the cannabis constituents delta-9-tetrahydrocannabinol (THC), cannabidiol (CBD), and cannabinol moderately inhibit the CYP2C9-mediated 7-hydroxylation of S-warfarin in a concentration-dependent manner. In vitro research also shows that cannabis extracts modestly inhibit the CYP2C9 metabolism of tolbutamide; extracts providing the specific cannabinoids CBD and cannabigerol (CBG) had stronger inhibitory effects than extracts containing THC and CBD.
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 basic idea with voriconazole and cannabis. Your body partly clears voriconazole using a liver enzyme called CYP2C9. Lab studies suggest that compounds in cannabis (THC and CBD) can slow that enzyme down a bit. In theory, that could let voriconazole build up a little more than expected, which might nudge up side effects like nausea, headache, visual changes (blurry vision or seeing flashes), dizziness, or stress on the liver.

I want to be straight with you though: this is based only on test-tube research, not real patient cases, so it's more of a 'keep an eye on it' than a red alert. Voriconazole already needs careful dosing, so it's worth a quick mention to your doctor or pharmacist rather than changing anything on your own.

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
Moderate

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

4 of 5

Voriconazole also falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES.

Theoretically, cannabis may increase the levels and adverse effects of CYP3A4 substrates.
In vitro research shows that cannabis can inhibit the activity of CYP3A4 enzymes, which might decrease the metabolism of CYP3A4 substrates. In vitro research also shows that cannabis extracts modestly inhibit the CYP3A4 metabolism of testosterone; extracts providing the specific cannabinoids CBD and cannabigerol (CBG) had stronger inhibitory effects than extracts containing THC and CBD.
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 idea with cannabis and your voriconazole. Voriconazole is cleared from your body partly by a liver enzyme called CYP3A4. Lab studies suggest cannabis can slow that enzyme down a bit. In theory, that could let voriconazole build up a little higher than usual, which might bump up its typical side effects, things like blurry or changed vision, light sensitivity, nausea, headache, dizziness, or liver irritation.

I want to be honest about the strength of this, though. So far this comes from test tube and lab research, not from real patient studies, so it may not turn into a noticeable problem for you. Voriconazole already has tricky blood levels that vary person to person, so it's worth a quick chat with your doctor or pharmacist before combining them.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Pellinen, P., Honkakoski, P., Stenback, F., Niemitz, M., Alhava, E., Pelkonen, O., Lang, M. A., and Pasanen, M. Cocaine N-demethylation and the metabolism-related hepatotoxicity can be prevented by cytochrome P450 3A inhibitors. Eur.J Pharmacol 1-3-1994;2 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
Moderate

CYTOCHROME P450 2C19 (CYP2C19) SUBSTRATES

5 of 5

Voriconazole also falls under CYTOCHROME P450 2C19 (CYP2C19) SUBSTRATES.

Cannabis may increase levels of drugs metabolized by CYP2C19.
Research shows that cannabidiol (CBD), a constituent of cannabis, inhibits CYP2C19. In clinical studies and case reports, cannabidiol use resulted in significant increases in the serum levels of topiramate, methadone, citalopram, omeprazole, and N-desmethylclobazam, the primary active metabolite of clobazam. These chemicals are metabolized by CYP2C19. Concomitant use of cannabis with CYP2C19 substrates may increase the risk for adverse effects from these substrates.
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 for voriconazole: your body partly clears this antifungal using a liver enzyme called CYP2C19. The CBD in cannabis can slow that enzyme down. When the enzyme works slower, voriconazole can build up in your blood and hang around longer, which means stronger effects and a higher chance of side effects.

With voriconazole, that could mean things like visual disturbances (blurry vision or seeing brighter light), liver irritation, nausea, or heart rhythm changes. To be fair, this concern is mostly theoretical, based on how these chemicals behave rather than direct studies with voriconazole. Still, since this is a serious medicine treating a serious infection, please check with your doctor or pharmacist before pairing it with cannabis.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Harvey DJ. Absorption, distribution, and biotransformation of the cannabinoids. Marijuana and Medicine. 1999;91-103. DOI
  2. Bornheim LM, Everhart ET, Li J, Correia MA. Characterization of cannabidiol-mediated cytochrome P450 inactivation. Biochem Pharmacol 1993;45(6):1323-31. PubMed
  3. Gaston TE, Bebin EM, Cutter GR, Liu Y, Szaflarski JP; UAB CBD Program. Interactions between cannabidiol and commonly used antiepileptic drugs. Epilepsia. 2017 Sep;58(9):1586-92. PubMed
  4. Devinsky O, Marsh E, Friedman D, et la. Cannabidiol in patients with treatment-resistant epilepsy: an open-label interventional trial. Lancet Neurol. 2016 Mar;15(3):270-8.
  5. Geffrey AL, Pollack SF, Bruno PL, Thiele EA. Drug-drug interaction between clobazam and cannabidiol in children with refractory epilepsy. Epilepsia. 2015 Aug;56(8):1246-51. PubMed
  6. Madden K, Tanco K, Bruera E. Clinically Significant Drug-Drug Interaction Between Methadone and Cannabidiol. Pediatrics. 2020;e20193256. PubMed
  7. Anderson LL, Doohan PT, Oldfield L, et al. Citalopram and Cannabidiol: In Vitro and In Vivo Evidence of Pharmacokinetic Interactions Relevant to the Treatment of Anxiety Disorders in Young People. J Clin Psychopharmacol. 2021. PubMed
  8. Nasrin S, Watson CJW, Perez-Paramo YX, Lazarus P. Cannabinoid Metabolites as Inhibitors of Major Hepatic CYP450 Enzymes, with Implications for Cannabis-Drug Interactions. Drug Metab Dispos 2021;49(12):1070-1080. PubMed
  9. 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

Cannabis Also Interacts With Other Medications

Cannabis has 2 major, 1,108 moderate, 25 minor known drug interactions in our database — the Voriconazole one above is among them. If you take anything else, check it against the full list below.

Major 2 Moderate 1,108 Minor 25 No known interaction 1,695 (incl. Voriconazole)
Taking anything else?

Check Another of Your Medications Against Cannabis

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

From our Q&A

Questions About Cannabis or Voriconazole

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

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

The most serious there right now: Activated Charcoal (major), Beer (major), Grapefruit (major), Siberian Cocklebur (major) and St. John's Wort (major).

By severity: 6 major · 159 moderate · 40 minor.

From our pharmacist’s overview on the Voriconazole page

“Voriconazole (Vfend) is a heavy-hitter antifungal, usually prescribed for dangerous infections like invasive aspergillosis, and its list of 205 interacting supplements includes six rated major, enough that anyone on this drug should read those entries before touching a supplement bottle. Most interactions run through the liver enzymes…”

Reviewed by 2 · Jul 18, 2026

Open the Voriconazole interaction page

One more smart check

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

We hold 21 real supplement products containing Cannabis, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Cannabis. Your product may carry other ingredients that interact with Voriconazole too, on top of Cannabis — 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 Cannabis and Voriconazole 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 Cannabis
Top 25%

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

29 days ago today
Medication Voriconazole
Steady interest

#2,484 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 Cannabis

What is Cannabis?

Cannabis
  • Chronic pain
  • Nausea and vomiting from chemotherapy
  • Muscle spasticity (e.g., multiple sclerosis)
  • Anxiety and stress
  • Sleep problems
  • Appetite stimulation

Cannabis contains many active compounds, mainly THC (which causes a 'high') and CBD (which does not). Some uses, such as chemotherapy-related nausea, certain seizure disorders, and muscle spasticity, have meaningful evidence, while many other popular uses are not well proven. It can cause real side effects and impairment, so talk to your doctor or pharmacist and follow your local laws before using it.

Read the full Cannabis monograph & all interactions
Medication

About Voriconazole

What Is Voriconazole Used For?

Brand name: Vfend

Voriconazole treats several serious fungal infections. Across all available forms — tablets, oral suspension, and intravenous (IV) injection — it is used for invasive aspergillosis (a dangerous mold infection), candidemia (Candida fungus in the bloodstream) in patients who are not neutropenic (not severely low on white blood cells), other deep-tissue Candida infections, and serious infections caused by Scedosporium apiospermum or Fusarium species in patients who cannot tolerate or have not responded to other antifungal treatments.

Esophageal candidiasis (a Candida infection of the esophagus, the swallowing tube) is also an approved use for most formulations. Note on the oral tablet form (generic voriconazole tablets): that specific tablet formulation is approved for patients aged 12 to 14 years weighing at least 50 kg, and all patients 15 years and older — not for younger or smaller children. The oral suspension and the IV injection are approved for patients 2 years and older for most of these conditions.

See full Voriconazole drug information
Keep checking

Other Drugs & Cannabis

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

2Major
1,108Moderate
25Minor
1,694No known interaction
2 Major 1,108 Moderate 25 Minor 1,694 No interaction
Major

2 interactions

Moderate

1,108 interactions

Showing 60 of 1,108 moderate interactions — see all 1,108 on the Cannabis page.

Minor

25 interactions

No interaction 1,694 drugs checked — show the list

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

Showing the 60 most looked-up of 1,694 medications checked with no known interaction — see the full Cannabis list.

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

Can you take Cannabis with Voriconazole?
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 5 interactions listed for Cannabis and Voriconazole?
Voriconazole belongs to more than one drug category, and Cannabis 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 Cannabis and Voriconazole 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 Voriconazole and Cannabis?

Our pharmacists answer your medication & supplement questions — free.

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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.