Drug & supplement interaction

Calotropis + Metolazone

Metolazone brand names: Diulo, Zaroxolyn, Mykrox.

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

Calotropis has a moderate interaction with Metolazone. Theoretically, concomitant use of calotropis and potassium depleting diuretics can increase the risk of cardiac glycoside toxicity due to potassium depletion.

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

Calotropis and Metolazone

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

Moderate

DIURETIC DRUGS

Why this applies to Metolazone

Metolazone falls under DIURETIC DRUGS — the group Calotropis interacts with.

Theoretically, concomitant use of calotropis and potassium depleting diuretics can increase the risk of cardiac glycoside toxicity due to potassium depletion. Some diuretics that can deplete potassium include chlorothiazide (Diuril), chlorthalidone (Thalitone), furosemide (Lasix), hydrochlorothiazide (HCTZ, Hydrodiuril, Microzide), and 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 thing with Metolazone (Zaroxolyn): it's a water pill that helps your body get rid of extra fluid and salt. One side effect is that it can also lower your potassium level over time. That's where Calotropis comes in. This plant naturally contains heart-acting compounds called cardiac glycosides, and when potassium runs low, those compounds can hit the heart harder, raising the risk of toxicity like an irregular or dangerous heartbeat.

I'll be honest, this concern is theoretical, based on how these substances work rather than real-world reports. Still, Calotropis can be genuinely toxic on its own, so I wouldn't take it internally. Please check with your doctor or pharmacist before combining anything like this with your Metolazone.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Robbers JE, Speedie MK, Tyler VE. Pharmacognosy and Pharmacobiotechnology. Baltimore, MD: Williams & Wilkins, 1996.
  2. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.

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

Calotropis Also Interacts With Other Medications

Calotropis has 97 moderate known drug interactions in our database — the Metolazone one above is one of them. If you take anything else, check it against the full list below.

Moderate 97 No known interaction 2,733 (incl. Metolazone)
Taking anything else?

Check Another of Your Medications Against Calotropis

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

Everything else you take

See Every Supplement That Interacts With Metolazone

This page covers Calotropis only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Metolazone page lists 222 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), Dolomite (major) and Lithium (major).

By severity: 8 major · 190 moderate · 24 minor.

Open the Metolazone interaction page

How much people look this up

Where Calotropis and Metolazone 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 Calotropis
Steady interest

#1,191 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Metolazone
Steady interest

#1,815 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 Calotropis

What is Calotropis?

  • Skin conditions and wounds (traditional, topical)
  • Joint pain and inflammation
  • Digestive complaints
  • Coughs and respiratory issues
  • Traditional Ayurvedic and folk remedies

Calotropis is a milkweed-family plant long used in traditional medicine, but its milky latex and other parts are potentially toxic and can harm the eyes, skin, and heart. Human evidence for any health benefit is very limited, and the risk of poisoning is real, so it should not be taken internally without expert medical supervision.

Read the full Calotropis monograph & all interactions
Medication

About Metolazone

What Is Metolazone Used For?

Brand names: Diulo, Zaroxolyn, Mykrox

Metolazone tablets are used to treat edema (excess fluid buildup) linked to congestive heart failure or kidney diseases — including nephrotic syndrome and conditions with reduced kidney function. They are also used to treat high blood pressure (hypertension), either alone or alongside other blood pressure medications.

Metolazone tablets may also be used during pregnancy when edema is caused by a medical condition rather than normal pregnancy changes — but routine use in otherwise healthy pregnant women is not appropriate.

See full Metolazone drug information
Keep checking

Other Drugs & Calotropis

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

0Major
97Moderate
0Minor
2,732No known interaction
97 Moderate 2,732 No interaction
Moderate

97 interactions

Showing 60 of 97 moderate interactions — see all 97 on the Calotropis page.

No interaction 2,732 drugs checked — show the list

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

Showing the 60 most looked-up of 2,732 medications checked with no known interaction — see the full Calotropis list.

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

Can you take Calotropis with Metolazone?
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 Calotropis and Metolazone 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 Metolazone and Calotropis?

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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.