Drug & supplement interaction

Magnesium + Verapamil

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

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

Magnesium has a moderate interaction with Verapamil. Magnesium can have additive effects with calcium channel blockers, although evidence is conflicting.

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

Magnesium and Verapamil

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

Moderate

CALCIUM CHANNEL BLOCKERS

Why this applies to Verapamil

Verapamil falls under CALCIUM CHANNEL BLOCKERS — the group Magnesium interacts with.

Magnesium can have additive effects with calcium channel blockers, although evidence is conflicting.
Magnesium inhibits calcium entry into smooth muscle cells and may therefore have additive effects with calcium channel blockers. Severe hypotension and neuromuscular blockades may occur when nifedipine is used with intravenous magnesium, although some contradictory evidence suggests that concurrent use of magnesium with nifedipine does not increase the risk of neuromuscular weakness. High doses of magnesium could theoretically have additive effects with other calcium channel blockers.
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 gist with verapamil and magnesium. Verapamil works partly by blocking calcium from entering your blood vessel and heart cells, which relaxes vessels and slows the heart. Magnesium does something similar in the background, so in theory the two could add up and push your blood pressure or heart rate down a little too much. That could show up as dizziness, lightheadedness, tiredness, or a slow pulse.

I want to be honest, though: this concern is mostly theoretical, based on how these work rather than strong studies, and the real-world reports involve high-dose intravenous magnesium, not a typical oral supplement. Everyday food amounts and standard magnesium pills are unlikely to cause trouble for most people. Still, if you have kidney issues or take large doses, check with your pharmacist or doctor first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Hansten PD, Horn JR. Drug Interactions Analysis and Management. Vancouver, WA: Applied Therapeutics Inc., 1997 and updates.
  2. Koontz SL, Friedman SA, Schwartz ML. Symptomatic hypocalcemia after tocolytic therapy with magnesium sulfate and nifedipine. Am J Obstet Gynecol. 2004;190(6):1773-6. PubMed
  3. Snyder SW, Cardwell MS. Neuromuscular blockade with magnesium sulfate and nifedipine. Am J Obstet Gynecol. 1989;161(1):35-6. PubMed
  4. Waisman GD, Mayorga LM, Cámera MI, et al. Magnesium plus nifedipine: potentiation of hypotensive effect in preeclampsia? Am J Obstet Gynecol. 1988;159(2):308-9. PubMed
  5. Magee, L. A., Miremadi, S., Li, J., Cheng, C., Ensom, M. H., Carleton, B., Cote, A. M., and von Dadelszen, P. Therapy with both magnesium sulfate and nifedipine does not increase the risk of serious magnesium-related maternal side effects in women with p

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

Magnesium Also Interacts With Other Medications

Magnesium has 6 major, 174 moderate, 114 minor known drug interactions in our database — the Verapamil one above is one of them. If you take anything else, check it against the full list below.

Major 6 Moderate 174 Minor 114 No known interaction 2,536 (incl. Verapamil)
Taking anything else?

Check Another of Your Medications Against Magnesium

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

From our Q&A

Questions About Magnesium 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 Magnesium 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 Magnesium 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 Magnesium as Part of a Dietary Supplement Product? Check It for Interactions

We hold 29,718 real supplement products containing Magnesium, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Magnesium. Your product may carry other ingredients that interact with Verapamil too, on top of Magnesium — 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 Magnesium 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 Magnesium
Top 10

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

29 days ago today
Medication Verapamil
Top 25%

#693 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 Magnesium

What is Magnesium?

Magnesium
  • Preventing or treating magnesium deficiency
  • Constipation
  • Muscle cramps
  • Sleep support
  • Anxiety and stress
  • Migraine prevention

Magnesium is an essential mineral your body needs for muscles, nerves, blood pressure, and many other functions, and supplements are useful for preventing or correcting deficiency. Some other uses, like easing constipation or preventing migraines, have reasonable support, while uses for sleep and anxiety are less proven. It is generally safe for most healthy people at recommended amounts, but talk to your pharmacist or doctor before starting, especially if you have kidney problems.

Read the full Magnesium 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 is used for high blood pressure, angina and some fast heart rhythms. Which uses apply depends on the product.

Immediate-release verapamil tablets are used for angina, certain rhythm problems and high blood pressure. Extended-release tablets and capsules are used for high blood pressure. Verapamil injection is given in a medical setting for fast heart rhythms.

See full Verapamil drug information
Keep checking

Other Drugs & Magnesium

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

6Major
174Moderate
114Minor
2,535No known interaction
6 Major 174 Moderate 114 Minor 2,535 No interaction
Major

6 interactions

Moderate

174 interactions

Showing 60 of 174 moderate interactions — see all 174 on the Magnesium page.

Minor

114 interactions

Showing 60 of 114 minor interactions — see all 114 on the Magnesium page.

No interaction 2,535 drugs checked — show the list

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

Showing the 60 most looked-up of 2,535 medications checked with no known interaction — see the full Magnesium list.

See the full Magnesium 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
Magnesium 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 Magnesium and Verapamil Together: Common Questions

Can you take Magnesium 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.
How serious is the Magnesium 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 Magnesium?

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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.