Drug & supplement interaction

Cannabidiol (cbd) + Ephedrine, Hydroxyzine, Theophylline

Ephedrine, Hydroxyzine, Theophylline brand names: Marax, Ami Rax.

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

Cannabidiol (cbd) has a moderate interaction with Ephedrine, Hydroxyzine, Theophylline. Cannabidiol may increase levels of drugs metabolized by CYP1A2.

Read the full interaction report
SeverityModerate
LikelihoodProbable
EvidenceA
What do Severity, Likelihood & Evidence mean?
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Interaction report

Cannabidiol (cbd) and Ephedrine, Hydroxyzine, Theophylline

Here is the interaction we found between these two, with the evidence behind it.

Moderate

CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES

Why this applies to Ephedrine, Hydroxyzine, Theophylline

Ephedrine, Hydroxyzine, Theophylline falls under CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES — the group Cannabidiol (cbd) interacts with.

Cannabidiol may increase levels of drugs metabolized by CYP1A2.
In vitro research shows that cannabidiol inhibits CYP1A2. Furthermore, clinical studies show that cannabidiol may inhibit the metabolism of caffeine, a CYP1A2 substrate. Two pharmacokinetic studies in healthy adults show that taking cannabidiol dosed 640 mg once up to 750 twice daily increases the area under the curve of caffeine. However, results are mixed over whether cannabidiol impacts peak serum levels of caffeine.
Severity Moderate Likelihood Probable Evidence A

Interaction 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..

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

This combination pill contains theophylline, which your body clears largely through a liver enzyme called CYP1A2. CBD can slow that enzyme down, so theophylline may build up higher than usual. That matters because theophylline has a narrow safety window, meaning even small increases can tip you from a helpful level into a toxic one. Watch for signs like a racing or pounding heart, nausea, jitteriness, trouble sleeping, headache, or in serious cases tremors or seizures.

The ephedrine in this product is also a stimulant, so any extra buildup could add to that wired, fast-heartbeat feeling. This concern is strongest with concentrated CBD doses, not trace amounts. Please don't change anything on your own. Talk with your pharmacist or doctor first, since they may want to check a theophylline level.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Yamaori S, Kushihara M, Yamamoto I, Watanabe K. Characterization of major phytocannabinoids, cannabidiol and cannabinol, as isoform-selective potent inhibitors of human CYP1 enzymes. Biochem Pharmacol 2010;79(11):1691-8.
  2. Thai C, Tayo B, Critchley D. A Phase 1 Open-Label, Fixed-Sequence Pharmacokinetic Drug Interaction Trial to Investigate the Effect of Cannabidiol on the CYP1A2 Probe Caffeine in Healthy Subjects. Clin Pharmacol Drug Dev. 2021. PubMed
  3. 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
  4. 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

Cannabidiol (cbd) Also Interacts With Other Medications

Cannabidiol (cbd) has 1,050 moderate known drug interactions in our database — the Ephedrine, Hydroxyzine, Theophylline one above is one of them. If you take anything else, check it against the full list below.

Moderate 1,050 No known interaction 1,780 (incl. Ephedrine, Hydroxyzine, Theophylline)
Taking anything else?

Check Another of Your Medications Against Cannabidiol (cbd)

Covers the 2,830 medications we’ve checked against Cannabidiol (cbd). Pick one to open its full report.

Everything else you take

See Every Supplement That Interacts With Ephedrine, Hydroxyzine, Theophylline

This page covers Cannabidiol (cbd) only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Ephedrine, Hydroxyzine, Theophylline page lists 199 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Black Tea (major), Caffeine (major), Coffee (major) and Ephedra (major).

By severity: 17 major · 143 moderate · 39 minor.

From our pharmacist’s overview on the Ephedrine, Hydroxyzine, Theophylline page

“For anyone taking Marax (ephedrine, hydroxyzine, theophylline), nothing on this page matters more than caffeine. Paired with the ephedrine in this combination, caffeine from coffee, teas, guarana, and similar herbs has been linked to dangerous blood pressure spikes, heart attack, and stroke, and those stimulant pairings account for mos…”

Reviewed by 2 · Jul 18, 2026

Open the Ephedrine, Hydroxyzine, Theophylline interaction page

How much people look this up

Where Cannabidiol (cbd) and Ephedrine, Hydroxyzine, Theophylline 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 Cannabidiol (cbd)
Top 25%

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

29 days ago today
Medication Ephedrine, Hydroxyzine, Theophylline
Top 5%

#141 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 Cannabidiol (cbd)

What is Cannabidiol (cbd)?

  • Anxiety and stress
  • Sleep problems
  • Chronic pain
  • Certain seizure disorders
  • Inflammation

CBD is a compound from the cannabis (hemp) plant that does not cause a 'high.' It has strong evidence only for certain rare seizure disorders (as a prescription drug), while most other popular uses are still backed by limited or early research. Product quality varies a lot, so talk with your pharmacist or doctor before using it, especially if you take other medicines.

Read the full Cannabidiol (cbd) monograph & all interactions
Keep checking

Other Drugs & Cannabidiol (cbd)

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

0Major
1,050Moderate
0Minor
1,779No known interaction
1,050 Moderate 1,779 No interaction
Moderate

1,050 interactions

Showing 60 of 1,050 moderate interactions — see all 1,050 on the Cannabidiol (cbd) page.

No interaction 1,779 drugs checked — show the list

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

Showing the 60 most looked-up of 1,779 medications checked with no known interaction — see the full Cannabidiol (cbd) list.

See the full Cannabidiol (cbd) interactions page
See every supplement checked against Ephedrine, Hydroxyzine, Theophylline, 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
Cannabidiol (cbd) monograph › Uses, safety, and every drug interaction in one place Ephedrine, Hydroxyzine, Theophylline supplement interactions › Every supplement checked against Ephedrine, Hydroxyzine, Theophylline, 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 Cannabidiol (cbd) and Ephedrine, Hydroxyzine, Theophylline Together: Common Questions

Can you take Cannabidiol (cbd) with Ephedrine, Hydroxyzine, Theophylline?
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.
How serious is the Cannabidiol (cbd) and Ephedrine, Hydroxyzine, Theophylline 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 Ephedrine, Hydroxyzine, Theophylline and Cannabidiol (cbd)?

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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.