Drug & supplement interaction

American Mistletoe + Methazolamide

Methazolamide brand name: Neptazane.

Major Interaction
Medically reviewed by · Updated February 2024
The bottom line Major

American Mistletoe has a major interaction with Methazolamide. American mistletoe contains phoratoxin, a compound toxic to humans that induces smooth muscle contraction and vasoconstriction, potentially increasing blood pressure and heart rate.

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

American Mistletoe and Methazolamide

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

Major

Antihypertensive Drugs

Why this applies to Methazolamide

Methazolamide falls under Antihypertensive Drugs — the group American Mistletoe interacts with.

American mistletoe contains phoratoxin, a compound toxic to humans that induces smooth muscle contraction and vasoconstriction, potentially increasing blood pressure and heart rate. Case reports of cardiotoxicity have been documented with American mistletoe, and it should not be used with antihypertensive drugs or by individuals with cardiac conditions. American mistletoe is uncommon in dietary supplements, and formulations containing it are generally homeopathic. European mistletoe, which lacks phoratoxin, is more commonly used.
Severity Major Likelihood Probable Evidence C

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 know if you take methazolamide for glaucoma: American mistletoe contains a toxin called phoratoxin that can tighten blood vessels and stir up your heart, which may push blood pressure and heart rate up. That works against medicines used to keep blood pressure steady. While methazolamide is mainly an eye-pressure medicine and not a classic blood pressure drug, it can shift your body's fluid and electrolyte balance, so adding something that strains the heart and vessels isn't a smart combination.

The good news is this plant is rarely found in real supplements, and the evidence here is modest, mostly case reports. Still, mistletoe is genuinely toxic, so I wouldn't take it. Please check with your pharmacist or doctor before using anything containing it.

Contact Dr. Brian directly if you have additional questions on this interaction

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

American Mistletoe Also Interacts With Other Medications

American Mistletoe has 189 major, known drug interactions in our database — the Methazolamide one above is one of them. If you take anything else, check it against the full list below.

Major 189 No known interaction 2,641 (incl. Methazolamide)
Taking anything else?

Check Another of Your Medications Against American Mistletoe

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

Everything else you take

See Every Supplement That Interacts With Methazolamide

This page covers American Mistletoe only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Methazolamide page lists 218 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Hellebore (major), Lithium (major), Oleander (major) and Tyramine (major).

By severity: 7 major · 187 moderate · 24 minor.

From our pharmacist’s overview on the Methazolamide page

“Methazolamide (Neptazane) treats glaucoma by lowering pressure inside the eye, and because it also has mild water-pill effects it can nudge blood pressure and potassium on its own. That is exactly where most of the 218 supplements on this page press, and the list earns real caution.”

Reviewed by 2 · Jul 18, 2026

Open the Methazolamide interaction page

How much people look this up

Where American Mistletoe and Methazolamide 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 American Mistletoe
Steady interest

#1,134 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Methazolamide
Steady interest

#2,449 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 American Mistletoe

What is American Mistletoe?

American Mistletoe
  • Traditional folk remedies
  • Digestive complaints
  • Decorative holiday plant

American mistletoe is a parasitic plant that is best known as a holiday decoration, not a proven medicine. It contains toxins that can harm the heart, gut, and blood vessels, and it has little reliable evidence to support any health use. We do not recommend taking it, and all parts should be kept away from children and pets.

Read the full American Mistletoe monograph & all interactions
Medication

About Methazolamide

What Is Methazolamide Used For?

Brand name: Neptazane

Methazolamide tablets are used to treat eye conditions where lowering intraocular pressure (pressure inside the eye) is expected to help. These include chronic open-angle glaucoma and secondary glaucoma.

Methazolamide tablets are also used before surgery in acute angle-closure glaucoma, when reducing eye pressure ahead of the procedure is needed. Note that long-term use in angle-closure glaucoma is not appropriate.

See full Methazolamide drug information
Keep checking

Other Drugs & American Mistletoe

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

189Major
0Moderate
0Minor
2,640No known interaction
189 Major 2,640 No interaction
Major

189 interactions

Showing 60 of 189 major interactions — see all 189 on the American Mistletoe page.

No interaction 2,640 drugs checked — show the list

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

Showing the 60 most looked-up of 2,640 medications checked with no known interaction — see the full American Mistletoe list.

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

Can you take American Mistletoe with Methazolamide?
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.
How serious is the American Mistletoe and Methazolamide 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 Methazolamide and American 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.