Drug & supplement interaction

Vitamin D + Methyclothiazide

Methyclothiazide brand names: Enduron, Aquatensen.

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

Vitamin D has a moderate interaction with Methyclothiazide. Theoretically, taking thiazide diuretics and high-dose vitamin D can increase the risk of hypercalcemia.

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

Vitamin D and Methyclothiazide

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

Moderate

THIAZIDE DIURETICS

Why this applies to Methyclothiazide

Methyclothiazide falls under THIAZIDE DIURETICS — the group Vitamin D interacts with.

Theoretically, taking thiazide diuretics and high-dose vitamin D can increase the risk of hypercalcemia.
Thiazide diuretics decrease urinary calcium excretion, which could lead to hypercalcemia if vitamin D supplements are taken concurrently. This has been reported in people being treated with vitamin D for hypoparathyroidism, and also in elderly people with normal parathyroid function who were taking a thiazide, vitamin D, and calcium-containing antacids daily.
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

Here's the simple version. Methyclothiazide is a water pill that tells your kidneys to hold onto a little more calcium instead of flushing it out. Vitamin D, on the other hand, helps your gut soak up more calcium from food. Put those two together, especially with high-dose vitamin D, and calcium can slowly climb higher than it should, a state called hypercalcemia.

If that happens, you might notice nausea, constipation, feeling unusually thirsty, frequent urination, weakness, or just being foggy and tired. To be fair, this is mostly based on scattered reports, and it's most likely when someone also takes calcium supplements or calcium-containing antacids. A normal daily vitamin D dose usually isn't a problem, but please don't change anything on your own. Ask your pharmacist or doctor whether a calcium check makes sense for you.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Tatro DS, ed. Drug Interactions Facts. Facts and Comparisons Inc., St. Louis, MO. 1999.
  2. Crowe M, Wollner L, Griffiths RA. Hypercalcemia following vitamin D and thiazide therapy in the elderly. Practitioner 1984;228:312-3.
  3. Parfitt AM. Thiazide-induced hypercalcemia in vitamin D-treated hypoparathyroidism. Ann Intern Med 1972;77:557-63. PubMed
  4. Thiazide diuretics and the risk of osteoporosis. Pharmacist's Letter/Prescriber's Letter 2003;19(11):191105.
  5. Escribano, J., Balaguer, A., Pagone, F., Feliu, A., and Roque, I. Figuls. Pharmacological interventions for preventing complications in idiopathic hypercalciuria. Cochrane.Database.Syst.Rev. 2009;(1):CD004754. 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

Vitamin D Also Interacts With Other Medications

Vitamin D has 79 moderate, 635 minor known drug interactions in our database — the Methyclothiazide one above is one of them. If you take anything else, check it against the full list below.

Moderate 79 Minor 635 No known interaction 2,116 (incl. Methyclothiazide)
Taking anything else?

Check Another of Your Medications Against Vitamin D

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

From our Q&A

Questions About Vitamin D or Methyclothiazide

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Vitamin D or Methyclothiazide, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

Everything else you take

See Every Supplement That Interacts With Methyclothiazide

This page covers Vitamin D only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Methyclothiazide page lists 227 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 · 192 moderate · 25 minor.

Open the Methyclothiazide interaction page

One more smart check

Taking Vitamin D as Part of a Dietary Supplement Product? Check It for Interactions

We hold 26,930 real supplement products containing Vitamin D, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Vitamin D. Your product may carry other ingredients that interact with Methyclothiazide too, on top of Vitamin D — 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 Vitamin D and Methyclothiazide 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 Vitamin D
Top 10

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

29 days ago today
Medication Methyclothiazide
Top half

#1,285 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 Vitamin D

What is Vitamin D?

Vitamin D
  • Bone health and osteoporosis
  • Correcting vitamin D deficiency
  • Immune system support
  • Muscle strength in older adults
  • General supplementation when sun exposure is low

Vitamin D is a fat-soluble vitamin that helps your body absorb calcium and is important for healthy bones, muscles, and immune function. Many people, especially those with low sun exposure, benefit from supplementation, but more is not always better and very high doses can be harmful. Ask your pharmacist or doctor whether a blood test and supplement make sense for you.

Read the full Vitamin D monograph & all interactions
Medication

About Methyclothiazide

What Is Methyclothiazide Used For?

Brand names: Enduron, Aquatensen

  • Methyclothiazide is used to treat high blood pressure. Methyclothiazide is also used to treat edema (fluid retention; excess fluid held in body tissues) caused by various medical problems, including heart, kidney, and liver disease and to treat edema caused by using certain medications including estrogen and corticosteroids. Methyclothiazide is in a class of medications called diuretics ('water pills'). It works by causing the kidneys to get rid of unneeded water and salt from the body into the urine.

  • High blood pressure is a common condition and when not treated, can cause damage to the brain, heart, blood vessels, kidneys and other parts of the body. Damage to these organs may cause heart disease, a heart attack, heart failure, stroke, kidney failure, loss of vision, and other problems. In addition to taking medication, making lifestyle changes will also help to control your blood pressure. These changes include eating a diet that is low in fat and salt, maintaining a healthy weight, exercising at least 30 minutes most days, not smoking, and using alcohol in moderation.

See full Methyclothiazide drug information
Keep checking

Other Drugs & Vitamin D

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

0Major
79Moderate
635Minor
2,115No known interaction
79 Moderate 635 Minor 2,115 No interaction
Moderate

79 interactions

Showing 60 of 79 moderate interactions — see all 79 on the Vitamin D page.

Minor

635 interactions

Showing 60 of 635 minor interactions — see all 635 on the Vitamin D page.

No interaction 2,115 drugs checked — show the list

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

Showing the 60 most looked-up of 2,115 medications checked with no known interaction — see the full Vitamin D list.

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

Can you take Vitamin D with Methyclothiazide?
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 Vitamin D and Methyclothiazide 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 Methyclothiazide and Vitamin D?

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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.