Drug & supplement interaction

European Mistletoe + Cyclothiazide

Cyclothiazide brand names: Fluidil, Anhydron.

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

European Mistletoe has a moderate interaction with Cyclothiazide. Theoretically, European mistletoe might increase the risk of hypotension when taken with antihypertensive drugs.

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

European Mistletoe and Cyclothiazide

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

Moderate

ANTIHYPERTENSIVE DRUGS

Why this applies to Cyclothiazide

Cyclothiazide falls under ANTIHYPERTENSIVE DRUGS — the group European Mistletoe interacts with.

Theoretically, European mistletoe might increase the risk of hypotension when taken with antihypertensive drugs.
Animal research suggests that European mistletoe extracts have hypotensive 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

Cyclothiazide is a thiazide-type water pill that lowers blood pressure by helping your body get rid of extra salt and fluid. Here's the concern: in animal studies, European mistletoe seems to nudge blood pressure down on its own. So if you paired it with a blood pressure medicine like cyclothiazide, those two lowering effects could stack up and push your pressure too low.

If that happened, you might feel dizzy, lightheaded, or faint, especially when standing up quickly. I'll be straight with you though: this is a theoretical caution based mainly on lab and animal work, not solid human evidence. Mistletoe should only be used under a doctor's supervision anyway. Please loop in your pharmacist or doctor before combining them.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Nazaruk J, Orlikowski P. Phytochemical profile and therapeutic potential of Viscum album L. Nat Prod Res. 2016;30(4):373-85.
  2. Khan T, Ali S, Qayyum R, Hussain I, Wahid F, Shah AJ. Intestinal and vascular smooth muscle relaxant effect of Viscum album explains its medicinal use in hyperactive gut disorders and hypertension. BMC Complement Altern Med. 2016 Jul 27;16:251. 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

European Mistletoe Also Interacts With Other Medications

European Mistletoe has 292 moderate known drug interactions in our database — the Cyclothiazide one above is one of them. If you take anything else, check it against the full list below.

Moderate 292 No known interaction 2,538 (incl. Cyclothiazide)
Taking anything else?

Check Another of Your Medications Against European Mistletoe

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

Everything else you take

See Every Supplement That Interacts With Cyclothiazide

This page covers European Mistletoe only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Cyclothiazide page lists 210 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: 10 major · 175 moderate · 25 minor.

From our pharmacist’s overview on the Cyclothiazide page

“Cyclothiazide (Fluidil, Anhydron) is a thiazide diuretic for high blood pressure and fluid retention, and its 210 supplement interactions warrant real vigilance, especially the ten rated major. Most entries pull in one of two directions.”

Reviewed by 2 · Jul 18, 2026

Open the Cyclothiazide interaction page

One more smart check

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

We hold 91 real supplement products containing European Mistletoe, each one broken down to its full ingredient list — and combination products often carry several ingredients besides European Mistletoe. Your product may carry other ingredients that interact with Cyclothiazide too, on top of European Mistletoe — 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 European Mistletoe and Cyclothiazide 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 European Mistletoe
Top half

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

29 days ago today
Medication Cyclothiazide
Top half

#1,252 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 European Mistletoe

What is European Mistletoe?

European Mistletoe
  • Cancer supportive care
  • Immune support
  • High blood pressure
  • Anxiety and stress
  • Inflammation

European mistletoe is a parasitic plant most studied as an injectable extract used alongside conventional cancer care in some European countries, mainly to improve quality of life rather than to cure cancer. The plant is toxic if eaten, and oral or self-treatment can be dangerous, so it should only be used under medical supervision. Talk to your pharmacist or doctor before using any mistletoe product.

Read the full European Mistletoe monograph & all interactions
Keep checking

Other Drugs & European Mistletoe

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

0Major
292Moderate
0Minor
2,537No known interaction
292 Moderate 2,537 No interaction
Moderate

292 interactions

Showing 60 of 292 moderate interactions — see all 292 on the European Mistletoe page.

No interaction 2,537 drugs checked — show the list

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

Showing the 60 most looked-up of 2,537 medications checked with no known interaction — see the full European Mistletoe list.

See the full European Mistletoe interactions page
See every supplement checked against Cyclothiazide, 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
European Mistletoe monograph › Uses, safety, and every drug interaction in one place Cyclothiazide supplement interactions › Every supplement checked against Cyclothiazide, 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 European Mistletoe and Cyclothiazide Together: Common Questions

Can you take European Mistletoe with Cyclothiazide?
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 European Mistletoe and Cyclothiazide 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 Cyclothiazide and European Mistletoe?

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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.