Drug & supplement interaction

Guarana + Ephedrine, Hydroxyzine, Theophylline

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

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

Ephedrine, Hydroxyzine, Theophylline falls into 3 drug categories that Guarana can interact with; the most serious is rated major. Theoretically, concomitant use might increase the risk for stimulant adverse effects.

Read the full interaction report
SeverityMajor
LikelihoodProbable
Interactions3
EvidenceD
What do Severity, Likelihood & Evidence mean?
Know someone taking this? Share
Facebook Post Reddit Email
On this page
Interaction report

Guarana and Ephedrine, Hydroxyzine, Theophylline

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

Why Are There 3 Interactions?

Guarana interacts with whole categories of medication. Ephedrine, Hydroxyzine, Theophylline falls into 3 of those categories, so it can interact with Guarana in 3 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Major).

Major

EPHEDRINE

1 of 3
Theoretically, concomitant use might increase the risk for stimulant adverse effects.
Guarana contains caffeine. Use of ephedrine with caffeine can increase the risk of stimulatory adverse effects. There is evidence that using ephedrine with caffeine might increase the risk of serious life-threatening or debilitating adverse effects such as hypertension, myocardial infarction, stroke, seizures, and death.
Severity Major Likelihood Probable Evidence D

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

Here's the thing to watch with this combination: your medicine (Marax) contains two stimulants already, ephedrine and theophylline. Guarana is loaded with caffeine, so adding it basically piles a third stimulant on top. These don't cancel each other out, they stack, and that's where the trouble comes in.

When you double up on stimulants like this, you can get a racing or pounding heart, a jump in blood pressure, jitteriness, trouble sleeping, and nausea. In more serious (but reported) cases people have had dangerous spikes in blood pressure, irregular heartbeats, or seizures. The evidence here is mostly anecdotal, but because it can be serious, I'd treat it carefully. Please check with your pharmacist or doctor before mixing guarana (or other caffeine and energy products) with this medication.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Vahedi K, Domingo V, Amarenco P, Bousser MG. Ischemic stroke in a sportsman who consumed MaHuang extract and creatine monohydrate for bodybuilding. J Neurol Neurosurg Psychiatr 2000;68:112-3.
  2. Haller CA, Benowitz NL. Adverse cardiovascular and central nervous system events associated with dietary supplements containing ephedra alkaloids. N Engl J Med 2000;343:1833-8. PubMed
  3. Kockler DR, McCarthy MW, Lawson CL. Seizure activity and unresponsiveness after hydroxycut ingestion. Pharmacotherapy 2001;21:647-51.. PubMed
Moderate

STIMULANT DRUGS

2 of 3

Why this applies to Ephedrine, Hydroxyzine, Theophylline

Ephedrine, Hydroxyzine, Theophylline falls under STIMULANT DRUGS — the group Guarana interacts with.

Theoretically, concomitant use might increase stimulant adverse effects.
Guarana contains caffeine. Due to the central nervous system (CNS) stimulant effects of caffeine, concomitant use with stimulant drugs can increase the risk of adverse 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 already packs a stimulant punch. Ephedrine revs up your heart and nervous system, and theophylline works a lot like caffeine itself, opening the airways but also stirring up the same jittery effects. Since guarana is basically concentrated caffeine, adding it stacks more stimulant on top of stimulant.

The concern here is mostly theoretical, based on how these ingredients work rather than strong studies, so it is not a sure thing. Still, piling on extra caffeine could make side effects like a racing or pounding heart, nervousness, trouble sleeping, tremor, or nausea more likely. Theophylline in particular has a narrow safety window. I would run this past your pharmacist or doctor before mixing them.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Institute of Medicine. Caffeine for the Sustainment of Mental Task Performance: Formulations for Military Operations. Washington, DC: National Academy Press, 2001. Available at: http://books.nap.edu/books/0309082587/html/index.html. DOI
Moderate

THEOPHYLLINE

3 of 3

Ephedrine, Hydroxyzine, Theophylline also falls under THEOPHYLLINE.

Theoretically, guarana might increase the levels and adverse effects of theophylline.
Guarana contains caffeine. Large amounts of caffeine might decrease theophylline clearance by 23% to 29%.
Severity Moderate Likelihood Probable Evidence D

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 product contains theophylline, an older breathing medicine that the body clears at a fairly fixed rate. The caffeine in guarana can slow that clearance (by roughly a quarter in studies), so theophylline can quietly build up in your blood. On top of that, your medicine already has ephedrine, a stimulant, and guarana adds even more caffeine to the mix.

What might you notice? A racing or pounding heart, jitteriness, trouble sleeping, nausea, headache, or feeling shaky. Theophylline has a narrow safety window, so even small increases can matter. This concern is mostly theoretical and based on pharmacology, but it's a sensible one. Please check with your pharmacist or doctor before pairing guarana with this medication.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Carrillo JA, Benitez J. Clinically significant pharmacokinetic interactions between dietary caffeine and medications. Clin Pharmacokinet 2000;39:127-53. PubMed

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

Guarana Also Interacts With Other Medications

Guarana has 7 major, 462 moderate, 185 minor known drug interactions in our database — the Ephedrine, Hydroxyzine, Theophylline one above is among them. If you take anything else, check it against the full list below.

Major 7 Moderate 462 Minor 185 No known interaction 2,176 (incl. Ephedrine, Hydroxyzine, Theophylline)
Taking anything else?

Check Another of Your Medications Against Guarana

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

Everything else you take

See Every Supplement That Interacts With Ephedrine, Hydroxyzine, Theophylline

This page covers Guarana 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

One more smart check

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

We hold 1,430 real supplement products containing Guarana, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Guarana. Your product may carry other ingredients that interact with Ephedrine, Hydroxyzine, Theophylline too, on top of Guarana — 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 Guarana 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 Guarana
Top 10%

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

29 days ago today
Medication Ephedrine, Hydroxyzine, Theophylline
Top 10%

#173 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 Guarana

What is Guarana?

Guarana
  • Energy and alertness
  • Reducing fatigue
  • Weight loss support
  • Athletic performance
  • Mental focus

Guarana is an Amazonian seed that is naturally high in caffeine, which explains most of its stimulant and energy effects. While it may give a short-term boost in alertness and reduce fatigue, strong evidence for weight loss or major performance gains is limited, and it carries the same risks as too much caffeine. Talk to your pharmacist or doctor before using it, especially if you have heart problems, anxiety, or are pregnant.

Read the full Guarana monograph & all interactions
Keep checking

Other Drugs & Guarana

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

7Major
462Moderate
185Minor
2,175No known interaction
7 Major 462 Moderate 185 Minor 2,175 No interaction
Major

7 interactions

Moderate

462 interactions

Showing 60 of 462 moderate interactions — see all 462 on the Guarana page.

Minor

185 interactions

Showing 60 of 185 minor interactions — see all 185 on the Guarana page.

No interaction 2,175 drugs checked — show the list

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

Showing the 60 most looked-up of 2,175 medications checked with no known interaction — see the full Guarana list.

See the full Guarana 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
Guarana 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 Guarana and Ephedrine, Hydroxyzine, Theophylline Together: Common Questions

Can you take Guarana with Ephedrine, Hydroxyzine, Theophylline?
This is rated a major interaction, so the combination is best avoided unless your doctor or pharmacist has specifically told you otherwise. Read the full details on this page and confirm with your pharmacist before combining them.
Why are there 3 interactions listed for Guarana and Ephedrine, Hydroxyzine, Theophylline?
Ephedrine, Hydroxyzine, Theophylline belongs to more than one drug category, and Guarana 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 Guarana and Ephedrine, Hydroxyzine, Theophylline interaction?
We rate it Major. This is a clinically significant combination that is generally best avoided, or used only under the direct supervision of your physician or pharmacist.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Still Have a Question About Ephedrine, Hydroxyzine, Theophylline and Guarana?

Our pharmacists answer your medication & supplement questions — free.

Ask a pharmacist

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.