Drug & supplement interaction

Guarumo + Penbutolol Sulfate

Penbutolol Sulfate brand name: Levatol.

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

Guarumo has a moderate interaction with Penbutolol Sulfate. Evidence from animal research suggests that aqueous and ethanolic extracts of guarumo leaf can lower blood pressure when administered intravenously to rats.

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

Guarumo and Penbutolol Sulfate

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

Moderate

ANTIHYPERTENSIVE DRUGS

Why this applies to Penbutolol Sulfate

Penbutolol Sulfate falls under ANTIHYPERTENSIVE DRUGS — the group Guarumo interacts with.

Evidence from animal research suggests that aqueous and ethanolic extracts of guarumo leaf can lower blood pressure when administered intravenously to rats. Theoretically, concomitant use of antihypertensive drugs with guarumo might enhance therapeutic effects and increase the risk of hypotension. Some antihypertensive drugs include captopril (Capoten), enalapril (Vasotec), losartan (Cozaar), valsartan (Diovan), diltiazem (Cardizem), amlodipine (Norvasc), hydrochlorothiazide (HydroDIURIL), furosemide (Lasix), and many others.
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: penbutolol (Levatol) already lowers your blood pressure and slows your heart rate. Guarumo, a leaf tea used in Latin American tradition, may also nudge blood pressure down a bit on its own. Put the two together and those effects could stack up, so you might end up lower than intended.

If that happens, you could feel dizzy, lightheaded, unusually tired, or faint when you stand up quickly. I'll be honest, though: this concern comes mostly from animal research, not solid human studies, so it's more of a theoretical caution than a proven problem. Casual amounts may matter less than concentrated supplement doses. Please loop in your pharmacist or doctor before combining them, and keep an eye on your blood pressure readings.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Vidrio, H., Garcia-Marquez, F., Reyes, J., and Soto, R. M. Hypotensive activity of Cecropia obtusifolia. J Pharm Sci 1982;71:475-76. PubMed
  2. Salas, I., Brenes, J. R., and Morales, O. M. Antihypertensive effect of Cecropia obtusifolia (Moraceae) leaf extract on rats. Rev Biol Trop 1987;35(1):127-30.
  3. Salas, I. G., Morales, O. M., and Brenes, J. R. Effect of chronic administration of Cecropia obtusifolia (Moraceae) on mean arterial pressure in rats. Rev Biol Trop 1987;35(2):359-62.

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

Guarumo Also Interacts With Other Medications

Guarumo has 504 moderate known drug interactions in our database — the Penbutolol Sulfate one above is one of them. If you take anything else, check it against the full list below.

Moderate 504 No known interaction 2,326 (incl. Penbutolol Sulfate)
Taking anything else?

Check Another of Your Medications Against Guarumo

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

Everything else you take

See Every Supplement That Interacts With Penbutolol Sulfate

This page covers Guarumo only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Penbutolol Sulfate page lists 139 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Hellebore (major), American Mistletoe (major), Indian Snakeroot (major) and Tyramine (major).

By severity: 5 major · 113 moderate · 21 minor.

From our pharmacist’s overview on the Penbutolol Sulfate page

“Penbutolol sulfate (Levatol) is a beta-blocker that lowers blood pressure and slows the heart, and its supplement file earns real vigilance, since five of the 139 ingredients on record carry a major rating. The great majority, 119 ingredients, tug on blood pressure one way or the other, some stacking with the drug until it falls too fa…”

Reviewed by 2 · Jul 18, 2026

Open the Penbutolol Sulfate interaction page

How much people look this up

Where Guarumo and Penbutolol Sulfate 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 Guarumo
Steady interest

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

29 days ago today
Medication Penbutolol Sulfate
Top half

#725 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 Guarumo

What is Guarumo?

Guarumo
  • Type 2 diabetes / blood sugar support
  • High blood pressure
  • Cough, asthma, and bronchitis
  • Heart failure symptoms
  • Liver and rheumatic complaints

Guarumo (Cecropia obtusifolia) is a tropical tree used in Latin American traditional medicine, most often as a leaf tea for diabetes and high blood pressure. Some early laboratory and small human studies suggest it may modestly affect blood sugar, but the evidence is limited and not strong enough to recommend it as a treatment. Talk with your pharmacist or doctor before using it, especially if you have a chronic condition or take medication.

Read the full Guarumo monograph & all interactions
Medication

About Penbutolol

What Is Penbutolol Used For?

Brand name: Levatol

  • Penbutolol is used to treat high blood pressure. Penbutolol is in a class of medications called beta blockers. It works by relaxing blood vessels and slowing heart rate to improve blood flow and decrease blood pressure.

See full Penbutolol drug information
Keep checking

Other Drugs & Guarumo

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

0Major
504Moderate
0Minor
2,325No known interaction
504 Moderate 2,325 No interaction
Moderate

504 interactions

Showing 60 of 504 moderate interactions — see all 504 on the Guarumo page.

No interaction 2,325 drugs checked — show the list

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

Showing the 60 most looked-up of 2,325 medications checked with no known interaction — see the full Guarumo list.

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

Can you take Guarumo with Penbutolol Sulfate?
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 Guarumo and Penbutolol Sulfate 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 Penbutolol Sulfate and Guarumo?

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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.