Drug & supplement interaction

Vitamin D + Verapamil

Verapamil brand names: Isoptin SR, Verelan, Isoptin, Calan SR, Verelan SR, and others.

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

Verapamil falls into 2 drug categories that Vitamin D can interact with; the most serious is rated moderate. Hypercalcemia induced by high-dose vitamin D can reduce the therapeutic effects of verapamil for arrhythmia.

Read the full interaction report
SeverityModerate
LikelihoodProbable
Interactions2
EvidenceB
What do Severity, Likelihood & Evidence mean?
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Interaction report

Vitamin D and Verapamil

These two interact in 2 distinct ways. Each one is explained separately below.

Why Are There 2 Interactions?

Vitamin D interacts with whole categories of medication. Verapamil falls into 2 of those categories, so it can interact with Vitamin D in 2 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).

Moderate

VERAPAMIL (Calan, others)

1 of 2
Hypercalcemia induced by high-dose vitamin D can reduce the therapeutic effects of verapamil for arrhythmia.
Hypercalcemia due to high doses of vitamin D can reduce the effectiveness of verapamil in atrial fibrillation. Avoid vitamin D doses above the tolerable upper intake level (4000 IU daily for adults) and monitor serum calcium levels in people taking vitamin D and verapamil concurrently.
Severity Moderate Likelihood Probable Evidence B

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 connection worth knowing: verapamil works partly by blocking calcium from flowing into your heart cells, which helps slow and steady the heartbeat. Vitamin D's main job is to raise calcium, so if you take very high doses over time, your blood calcium can climb too high (a state called hypercalcemia). When that happens, all that extra calcium can push back against verapamil and make it less effective, especially for controlling an irregular heartbeat like atrial fibrillation. You might notice your heart rate creeping up or feel fluttering or palpitations.

The good news: normal everyday doses are not the concern here. The issue is large amounts, generally above 4000 IU a day. If you take both, ask your doctor or pharmacist whether a vitamin D blood level and a calcium check make sense for you. Please don't change either one on your own.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Bar-Or D, Yoel G. Calcium and calciferol antagonize effect of verapamil in atrial fibrillation. Br Med J 1981;282:1585-6.
Minor

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

2 of 2

Why this applies to Verapamil

Verapamil falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES — the group Vitamin D interacts with.

Vitamin D might induce CYP3A4 enzymes and reduce the bioavailability of CYP3A4 substrates.
There is some concern that vitamin D might induce CYP3A4. In vitro research suggests that vitamin D induces CYP3A4 transcription. Additionally, observational research has found that increased UV light exposure and serum vitamin D levels are associated with decreased serum levels of CYP3A4 substrates such as tacrolimus and sirolimus, while no association between UV light exposure or vitamin D levels and levels of mycophenolic acid, a non-CYP3A4 substrate, was found. A small, low-quality clinical study shows that taking vitamin D reduces levels of the CYP3A4 substrate atorvastatin and its active metabolites by up to 55%; however, the clinical effects of atorvastatin were not reduced. While researchers theorized that vitamin D might induce CYP3A4, this proposed mechanism was not specifically studied.
Severity Minor 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 gist with these two together. Verapamil is cleared from your body partly by a liver enzyme called CYP3A4. There's a theory that vitamin D may gently speed that enzyme up. If that happened, your body could clear verapamil a little faster, which in theory might make it work slightly less well (think blood pressure creeping up, or less control over chest pain or heart rate).

The honest part: this is mostly lab-based thinking, not something we see causing real problems in people taking verapamil. Everyday vitamin D doses are very unlikely to throw off your treatment. Just keep taking your vitamin D as directed, watch your blood pressure or symptoms, and check with your pharmacist or doctor before making any changes.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Schwartz JB. Effects of vitamin D supplementation in atorvastatin-treated patients: A new drug interaction with an unexpected consequence. Clin Pharmacol Ther 2009;85:198-203. PubMed
  2. Wang Z, Schuetz EG, Xu Y, Thummel KE. Interplay between vitamin D and the drug metabolizing enzyme CYP3A4. J Steroid Biochem Mol Biol 2013;136:54-8. 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 Verapamil one above is among them. If you take anything else, check it against the full list below.

Moderate 79 Minor 635 No known interaction 2,116 (incl. Verapamil)
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 Verapamil

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 Verapamil, 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 Verapamil

This page covers Vitamin D only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Verapamil page lists 295 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), Beer (major) and Coleus (major).

By severity: 10 major · 245 moderate · 40 minor.

From our pharmacist’s overview on the Verapamil page

“This is one of the longer interaction lists we publish, and with verapamil (Calan, Verelan) it warrants genuine care, starting with the ten major-rated entries. Verapamil lowers blood pressure and slows the heart, so most of the 295 ingredients on file either push that effect further than intended or change how much of the drug reaches…”

Reviewed by 2 · Jul 18, 2026

Open the Verapamil 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 Verapamil 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 Verapamil 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

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

29 days ago today
Medication Verapamil
Top 25%

#705 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 Verapamil

What Is Verapamil Used For?

Brand names: Isoptin SR, Verelan, Isoptin, Calan SR, Verelan SR, Calan, Covera HS, Verap, Veramil

Verapamil tablets and film-coated tablets are used to treat angina — including vasospastic (Prinzmetal's) angina, unstable angina, and chronic stable angina — as well as certain abnormal heart rhythms (arrhythmias) and high blood pressure (essential hypertension). For arrhythmias, regular-release tablets are used alongside digoxin to control heart rate in atrial flutter or atrial fibrillation, and to help prevent episodes of paroxysmal supraventricular tachycardia (SVT), a type of rapid heartbeat.

Extended-release and sustained-release oral forms (tablets and capsules) are indicated specifically for high blood pressure. Verapamil hydrochloride injection is used in hospital settings for rapid conversion of SVT to normal rhythm and for temporary control of fast heart rates in atrial flutter or atrial fibrillation.

See full Verapamil 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 Verapamil, 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 Verapamil supplement interactions › Every supplement checked against Verapamil, ranked by severity Verapamil 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 Verapamil Together: Common Questions

Can you take Vitamin D with Verapamil?
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.
Why are there 2 interactions listed for Vitamin D and Verapamil?
Verapamil belongs to more than one drug category, and Vitamin D interacts with each of those categories a little differently. We list every one so nothing is missed — your overall risk is driven by the most serious of them.
How serious is the Vitamin D and Verapamil 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 Verapamil 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.