Drug & supplement interaction

Delta-9-tetrahydrocannabinol (thc) + Acetaminophen, Caffeine, Codeine, Salicylamide

Acetaminophen, Caffeine, Codeine, Salicylamide brand names: Codalan No.1, Codalan No.2, Codalan No.3.

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

Acetaminophen, Caffeine, Codeine, Salicylamide falls into 3 drug categories that Delta-9-tetrahydrocannabinol (thc) can interact with; the most serious is rated moderate. Theoretically, THC might have additive effects if used with other CNS depressants.

Read the full interaction report
SeverityModerate
LikelihoodPossible
Interactions3
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Delta-9-tetrahydrocannabinol (thc) and Acetaminophen, Caffeine, Codeine, Salicylamide

These two interact in 3 distinct ways. Each one is explained separately below.

Why Are There 3 Interactions?

Delta-9-tetrahydrocannabinol (thc) interacts with whole categories of medication. Acetaminophen, Caffeine, Codeine, Salicylamide falls into 3 of those categories, so it can interact with Delta-9-tetrahydrocannabinol (thc) in 3 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).

Moderate

CNS DEPRESSANTS

1 of 3

Why this applies to Acetaminophen, Caffeine, Codeine, Salicylamide

Acetaminophen, Caffeine, Codeine, Salicylamide falls under CNS DEPRESSANTS — the group Delta-9-tetrahydrocannabinol (thc) interacts with.

Theoretically, THC might have additive effects if used with other CNS depressants.
Cannabis containing THC can have CNS depressant effects. Combining THC with other CNS depressants might result in additive or synergistic effects.
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

This combination product contains codeine, an opioid that can slow down your brain and body. THC from cannabis can do something similar, making you drowsy, foggy, and slow to react. So the concern here is simple: stacking the two together may add up. You could feel sleepier than expected, more dizzy or lightheaded, and have a harder time concentrating or driving safely.

To be fair, this warning is theoretical, based on how both substances act rather than strong studies, so it may not hit everyone the same way. Still, the caffeine in this product won't reliably cancel out that sedation. Please don't change anything on your own. Talk with your pharmacist or doctor, especially before driving or operating machinery.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Marinol Prescribing Information. Solvay Pharmaceuticals, Rev March 2008. Available at: http://www.solvaypharmaceuticals-us.com/static/wma/pdf/1/3/2/5/0/004InsertText500012RevMar2008.pdf (Accessed 2 July 2009).
  2. Hollister, L. E. Interactions of cannabis with other drugs in man. NIDA Res.Monogr 1986;68:110-116. DOI
  3. van Dam CJ, van der Schrier R, van Velzen M, et al. Inhaled Delta(9)-tetrahydrocannabinol does not enhance oxycodone-induced respiratory depression: randomised controlled trial in healthy volunteers. Br J Anaesth 2023;130(4):485-493.
Moderate

CYTOCHROME P450 2E1 (CYP2E1) SUBSTRATES

2 of 3

Acetaminophen, Caffeine, Codeine, Salicylamide also falls under CYTOCHROME P450 2E1 (CYP2E1) SUBSTRATES.

Theoretically, THC might decrease the levels and clinical effects of CYP2E1 substrates.
In vitro research shows that cannabis containing THC can induce the activity of CYP2E1, which might increase the metabolism of CYP2E1 substrates. It is unclear if this effect is due to THC, other constituents, or the combination.
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 piece that matters in this combo pill: the acetaminophen portion is partly handled by a liver enzyme called CYP2E1. Some early lab studies hint that THC might speed that enzyme up, which could shift how acetaminophen is broken down. The concern with acetaminophen is that one of its breakdown products can be hard on the liver, so faster processing through this pathway is something to be mindful of, especially at higher acetaminophen doses or with regular drinking.

I want to be honest about the strength here: this is only test-tube and animal data, and it isn't even clear THC itself is the cause. So this is more theoretical than proven. If you use cannabis and take this medicine, just keep your acetaminophen within recommended limits and check in with your pharmacist or doctor.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Sheweita, S. A. Narcotic drugs change the expression of cytochrome P450 2E1 and 2C6 and other activities of carcinogen-metabolizing enzymes in the liver of male mice. Toxicology 9-30-2003;191(2-3):133-142. PubMed
Minor

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

3 of 3

Acetaminophen, Caffeine, Codeine, Salicylamide also falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES.

Theoretically, THC may increase the levels and clinical effects of CYP3A4 substrates.
In vitro research shows that cannabis containing THC might modestly inhibit the activity of CYP3A4 enzymes, which might decrease the metabolism of CYP3A4 substrates. It is unclear if this effect is due to THC, other constituents, or the combination. In vitro research also shows that cannabis extracts containing THC modestly inhibit the CYP3A4 metabolism of testosterone; extracts providing the specific cannabinoids cannabidiol (CBD) or cannabigerol (CBG) alone had stronger inhibitory effects than extracts containing both THC and CBD. Conversely, a crossover clinical study in healthy adults shows that oral THC does not inhibit CYP3A4.
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

This combination pill contains codeine, which is interesting here. Codeine is actually a prodrug, meaning your body has to convert it into morphine to relieve pain (that step relies mostly on the CYP2D6 enzyme, not CYP3A4). The theory on file is that THC might mildly slow down CYP3A4, the enzyme that handles many medicines. For this product that effect would be tiny, and a small side path of codeine does run through CYP3A4.

Honestly, this is a very weak concern. It comes only from lab and test-tube studies, and one human study showed oral THC did not block CYP3A4 at all. So a real-world spike in drowsiness, dizziness, or stomach upset from this is unlikely. Still, both THC and codeine can make you sleepy, so go easy and check with your pharmacist or doctor 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
  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 Acetaminophen, Caffeine, Codeine, Salicylamide 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. Acetaminophen, Caffeine, Codeine, Salicylamide)
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 Acetaminophen, Caffeine, Codeine, Salicylamide

This page covers Delta-9-tetrahydrocannabinol (thc) only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Acetaminophen, Caffeine, Codeine, Salicylamide page lists 303 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: 1,4-butanediol (major), Activated Charcoal (major), Asarabacca (major), Beer (major) and Ephedra (major).

By severity: 15 major · 244 moderate · 44 minor.

Open the Acetaminophen, Caffeine, Codeine, Salicylamide interaction page

How much people look this up

Where Delta-9-tetrahydrocannabinol (thc) and Acetaminophen, Caffeine, Codeine, Salicylamide 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

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

29 days ago today
Medication Acetaminophen, Caffeine, Codeine, Salicylamide
Steady interest

#1,458 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 Acetaminophen, Caffeine, Codeine, Salicylamide, 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 Acetaminophen, Caffeine, Codeine, Salicylamide supplement interactions › Every supplement checked against Acetaminophen, Caffeine, Codeine, Salicylamide, 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 Acetaminophen, Caffeine, Codeine, Salicylamide Together: Common Questions

Can you take Delta-9-tetrahydrocannabinol (thc) with Acetaminophen, Caffeine, Codeine, Salicylamide?
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 3 interactions listed for Delta-9-tetrahydrocannabinol (thc) and Acetaminophen, Caffeine, Codeine, Salicylamide?
Acetaminophen, Caffeine, Codeine, Salicylamide 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 Acetaminophen, Caffeine, Codeine, Salicylamide 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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