Drug & supplement interaction

Cannabis + Isoniazid, Pyrazinamide, Rifampin

Isoniazid, Pyrazinamide, Rifampin brand name: Rifater.

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

Isoniazid, Pyrazinamide, Rifampin falls into 4 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
Interactions4
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Cannabis and Isoniazid, Pyrazinamide, Rifampin

These two interact in 4 distinct ways. Each one is explained separately below.

Why Are There 4 Interactions?

Cannabis interacts with whole categories of medication. Isoniazid, Pyrazinamide, Rifampin falls into 4 of those categories, so it can interact with Cannabis in 4 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 4

Why this applies to Isoniazid, Pyrazinamide, Rifampin

Isoniazid, Pyrazinamide, Rifampin 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 thing to know if you take Rifater (the combo pill of isoniazid, pyrazinamide, and rifampin) for tuberculosis. One of these ingredients, isoniazid, can block a liver enzyme called CYP2C9. That same enzyme helps your body break down THC, the part of cannabis that gets you high. So in theory, the isoniazid could slow how fast cannabis clears, letting it build up a bit more than usual.

What that might feel like is a stronger or longer cannabis effect: more drowsiness, dizziness, a faster heartbeat, dry mouth, or feeling more impaired than expected. I'll be honest, this is a theoretical concern based on how the enzymes work, not something proven in studies, so don't panic. Still, please run it by 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 3A4 (CYP3A4) INHIBITORS

2 of 4

Isoniazid, Pyrazinamide, Rifampin 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 something worth knowing if you're on Rifater (isoniazid, pyrazinamide, and rifampin) for tuberculosis. One piece of this combo, isoniazid, can block a liver enzyme called CYP3A4, which is the same enzyme that helps break down THC, the active part of cannabis. In theory, that means THC could clear out of your system more slowly and pile up a bit, leaving you feeling more of its effects, like stronger drowsiness, dizziness, a racing heart, or feeling more impaired than expected.

I want to be honest with you: this is a theoretical concern based on how these drugs work, not something proven in real patients. Still, it's smart to mention any cannabis use to your doctor or pharmacist while you're on TB treatment, since these medicines are already hard on the liver.

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) INDUCERS

3 of 4

Isoniazid, Pyrazinamide, Rifampin also falls under CYTOCHROME P450 3A4 (CYP3A4) INDUCERS.

Theoretically, CYP3A4 inducers might reduce the levels and clinical 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 practical takeaway for Rifater. The rifampin part of this combination pill is a strong 'speed-up' signal for a liver enzyme called CYP3A4, which is one of the pathways that breaks down THC, the main active compound in cannabis. So if you're using cannabis while on Rifater, your body may clear the THC faster than usual. In plain terms, your cannabis could feel weaker or wear off sooner, and you might be tempted to use more to get the same effect.

This is a theoretical concern based on how these drugs work, not something proven in studies, so it's on the milder end. Still, never adjust your TB medication, since skipping or stopping it can let the infection come roaring back. If you notice a change, talk it over with your pharmacist or doctor.

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) INDUCERS

4 of 4

Isoniazid, Pyrazinamide, Rifampin also falls under CYTOCHROME P450 2C9 (CYP2C9) INDUCERS.

Theoretically, drugs that are CYP2C9 inducers might decrease the 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 gist of this one. Rifampin (part of the Rifater combination) is one of the body's strongest enzyme revvers. It speeds up a liver enzyme called CYP2C9, and that same enzyme helps break down THC, the active part of cannabis. So in theory, if you're taking Rifater, your body may clear THC faster, meaning your cannabis could feel weaker or wear off sooner than you expect.

Notice the direction here: it's the medication affecting the cannabis, not the other way around. This is a theoretical concern based on how the drugs work, not from strong human studies, so don't panic. Importantly, please don't skip or change your TB medicines, since finishing the full course matters a lot. If you use cannabis, just mention it to your pharmacist or doctor so they can keep an eye on things.

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.

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 Isoniazid, Pyrazinamide, Rifampin 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. Isoniazid, Pyrazinamide, Rifampin)
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 Isoniazid, Pyrazinamide, Rifampin

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 Isoniazid, Pyrazinamide, Rifampin, 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 Isoniazid, Pyrazinamide, Rifampin

This page covers Cannabis only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Isoniazid, Pyrazinamide, Rifampin page lists 137 supplements it has a documented interaction with, worst first, each one explained.

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

By severity: 8 major · 109 moderate · 20 minor.

From our pharmacist’s overview on the Isoniazid, Pyrazinamide, Rifampin page

“Rifater combines isoniazid, pyrazinamide, and rifampin for tuberculosis, a regimen that runs for months and already works the liver hard, so this list warrants genuine care rather than a quick skim. Of the 137 supplements and herbs on file, eight rate major, and the largest single group, 38 ingredients, adds extra liver strain on top o…”

Reviewed by 2 · Jul 18, 2026

Open the Isoniazid, Pyrazinamide, Rifampin 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 Isoniazid, Pyrazinamide, Rifampin 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 Isoniazid, Pyrazinamide, Rifampin 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%

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

29 days ago today
Medication Isoniazid, Pyrazinamide, Rifampin
Top 5%

#98 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
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 Isoniazid, Pyrazinamide, Rifampin, 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 Isoniazid, Pyrazinamide, Rifampin supplement interactions › Every supplement checked against Isoniazid, Pyrazinamide, Rifampin, 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 Cannabis and Isoniazid, Pyrazinamide, Rifampin Together: Common Questions

Can you take Cannabis with Isoniazid, Pyrazinamide, Rifampin?
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 4 interactions listed for Cannabis and Isoniazid, Pyrazinamide, Rifampin?
Isoniazid, Pyrazinamide, Rifampin 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 Isoniazid, Pyrazinamide, Rifampin 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 Isoniazid, Pyrazinamide, Rifampin and Cannabis?

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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.