Drug & supplement interaction

Fever Bark + Enalapril Maleate, Hydrochlorothiazide

Enalapril Maleate, Hydrochlorothiazide brand name: Vaseretic.

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

Fever Bark has a moderate interaction with Enalapril Maleate, Hydrochlorothiazide. Theoretically, fever bark might alter the effects of antihypertensive drugs.

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

Fever Bark and Enalapril Maleate, Hydrochlorothiazide

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

Moderate

ANTIHYPERTENSIVE DRUGS

Why this applies to Enalapril Maleate, Hydrochlorothiazide

Enalapril Maleate, Hydrochlorothiazide falls under ANTIHYPERTENSIVE DRUGS — the group Fever Bark interacts with.

Theoretically, fever bark might alter the effects of antihypertensive drugs.
Yohimbine, a constituent of fever bark, is an alpha-2 adrenoceptor antagonist and has been reported to increase blood pressure in clinical research. Conversely, reserpine can reduce both systolic and diastolic blood pressure. Theoretically, concomitant use of fever bark and antihypertensive drugs can interfere with blood pressure control.
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

Vaseretic combines enalapril (an ACE inhibitor) with hydrochlorothiazide (a water pill) to keep your blood pressure in a healthy range. The concern with fever bark is that it carries a mix of plant alkaloids that tug your blood pressure in different directions. One of them, a yohimbine-like compound, can raise blood pressure, which could work against your medication and leave your numbers higher than expected. Another, a reserpine-like compound, can lower it, possibly adding to your drug's effect and causing dizziness, lightheadedness, or feeling faint when you stand up.

Keep in mind this is theoretical, based on how these compounds behave rather than solid human studies. Still, since the push could go either way and make your blood pressure hard to predict, I'd run any use of fever bark past your doctor or pharmacist first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Leung AY, Foster S. Encyclopedia of Common Natural Ingredients Used in Food, Drugs and Cosmetics. 2nd ed. New York, NY: John Wiley & Sons, 1996.
  2. Kearney T, Tu N, Haller C. Adverse drug events associated with yohimbine-containing products: a retrospective review of the California Poison Control System reported cases. Ann Pharmacother 2010;44:1022-9. PubMed
  3. Lobay D. Rauwolfia in the Treatment of Hypertension. Integr Med (Encinitas). 2015 Jun;14(3):40-6.
  4. Sheldon MB, Kotte JH. Effect of Rauwolfia serpentina and reserpine on the blood pressure in essential hypertension; a long-term double-blind study. Circulation. 1957 Aug;16(2):200-6.

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

Fever Bark Also Interacts With Other Medications

Fever Bark has 40 major, 673 moderate, 87 minor known drug interactions in our database — the Enalapril Maleate, Hydrochlorothiazide one above is one of them. If you take anything else, check it against the full list below.

Major 40 Moderate 673 Minor 87 No known interaction 2,030 (incl. Enalapril Maleate, Hydrochlorothiazide)
Taking anything else?

Check Another of Your Medications Against Fever Bark

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

Everything else you take

See Every Supplement That Interacts With Enalapril Maleate, Hydrochlorothiazide

This page covers Fever Bark only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Enalapril Maleate, Hydrochlorothiazide page lists 238 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), Asarabacca (major) and Dolomite (major).

By severity: 11 major · 200 moderate · 27 minor.

From our pharmacist’s overview on the Enalapril Maleate, Hydrochlorothiazide page

“If you take Vaseretic (enalapril with hydrochlorothiazide) for blood pressure, check this list carefully before adding any supplement; 11 of the 238 entries are rated major. Most run one of two ways: herbs that also drop blood pressure and can take it too low, or ones that raise it and fight the medicine.”

Reviewed by 2 · Jul 18, 2026

Open the Enalapril Maleate, Hydrochlorothiazide interaction page

How much people look this up

Where Fever Bark and Enalapril Maleate, Hydrochlorothiazide 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 Fever Bark
Steady interest

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

29 days ago today
Medication Enalapril Maleate, Hydrochlorothiazide
Top 25%

#297 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 Fever Bark

What is Fever Bark?

Fever Bark
  • Fever
  • Diarrhea
  • Malaria (traditional)
  • Digestive complaints
  • Bitter tonic

Fever bark is the bark of the Australian tree Alstonia constricta, used in traditional medicine for fever, diarrhea, and infections. There is very little reliable human research to support these uses, and the bark contains potent alkaloids that may cause serious side effects. It is best avoided unless used under direct medical supervision.

Read the full Fever Bark monograph & all interactions
Medication

About Enalapril and Hydrochlorothiazide

What Is Enalapril and Hydrochlorothiazide Used For?

Brand name: Vaseretic

Enalapril and hydrochlorothiazide tablets — sold under brand names including Vaseretic and Enalapril maleate and hydrochlorothiazide — are used to treat high blood pressure (hypertension). This combination is not meant as the first treatment tried; it's generally used when a single blood pressure medicine hasn't done the job on its own.

Because this is a fixed-dose combination, your doctor will typically adjust each medicine separately first, then switch you to the combination tablet once the right doses are found.

See full Enalapril and Hydrochlorothiazide drug information
Keep checking

Other Drugs & Fever Bark

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

40Major
673Moderate
87Minor
2,029No known interaction
40 Major 673 Moderate 87 Minor 2,029 No interaction
Major

40 interactions

Moderate

673 interactions

Showing 60 of 673 moderate interactions — see all 673 on the Fever Bark page.

Minor

87 interactions

Showing 60 of 87 minor interactions — see all 87 on the Fever Bark page.

No interaction 2,029 drugs checked — show the list

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

Showing the 60 most looked-up of 2,029 medications checked with no known interaction — see the full Fever Bark list.

See the full Fever Bark interactions page
See every supplement checked against Enalapril Maleate, Hydrochlorothiazide, 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
Fever Bark monograph › Uses, safety, and every drug interaction in one place Enalapril Maleate, Hydrochlorothiazide supplement interactions › Every supplement checked against Enalapril Maleate, Hydrochlorothiazide, ranked by severity Enalapril and Hydrochlorothiazide 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 Fever Bark and Enalapril Maleate, Hydrochlorothiazide Together: Common Questions

Can you take Fever Bark with Enalapril Maleate, Hydrochlorothiazide?
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 Fever Bark and Enalapril Maleate, Hydrochlorothiazide 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 Enalapril Maleate, Hydrochlorothiazide and Fever Bark?

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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.