Drug & supplement interaction

Zone Diet + Diltiazem

Diltiazem brand names: Cardizem, Cardizem SR, Diltiaz SR, Cardizem CD, Tiazac, and others.

No Known Interaction
Medically reviewed by · Updated June 2026 · Pair last verified Sep 20, 2026
The bottom line No known interaction

We found no known interaction between Zone Diet and Diltiazem in our sources. Absence of a documented interaction is not the same as proven safety, and does not guarantee one does not exist. Do not start, stop, or change a medication or supplement based on this page; confirm with your pharmacist or doctor first.

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Interaction report

Zone Diet and Diltiazem

We checked these two against our interaction database. Here is what we found.

No Known Interaction Found

We did not find a documented interaction between Diltiazem and Zone Diet in our sources. This does not guarantee that the combination is completely free of risk — research on Zone Diet alongside specific medications may be limited.

Worth understanding: our licensed dataset holds no drug-interaction record for Zone Diet at all — not against Diltiazem, and not against any other medication we track. This verdict therefore rests on the absence of any recorded data, not on research that looked at this combination and found nothing. We cannot rule an interaction out.

Zone Diet is an eating pattern rather than something you take. Ask your pharmacist or doctor before changing how you eat while on a prescribed medicine: some medicines are dosed around meals, and a change in diet can change how they work. Do not stop a prescribed medicine on your own.

Always talk with your pharmacist or doctor before making changes to your medications or supplements, particularly if you take several medications or have an ongoing health condition.

Zone Diet safety at a glance

Zone Diet overall Use caution Generally safe for healthy adults but it is restrictive and may not suit everyone.
Pregnancy Use caution Calorie- or carb-restricted diets may not meet pregnancy nutrient needs, so check with your doctor first.
Breastfeeding Use caution Nursing needs extra calories and nutrients, so discuss any restrictive diet with your provider.

Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Diltiazem and Zone Diet? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
What to actually watch for

What Diltiazem’s Own FDA Label Lists

This is not an interaction — none of it involves Zone Diet. These are the most notable effects listed in the ADVERSE REACTIONS section of Diltiazem’s own FDA label, for the medication by itself. Knowing the drug’s own list makes it easier to work out the likely cause if something new turns up while you follow Zone Diet and take the medicine. 10 of them are worth acting on rather than waiting out — marked below.

  • Bleeding in the gut Worth acting on
  • A slow heartbeat Worth acting on
  • Shortness of breath Worth acting on mentioned in 9.6% of FDA reports for Diltiazem
  • Fainting Worth acting on
  • An irregular heartbeat Worth acting on
  • A severe skin reaction Worth acting on
  • Chest pain Worth acting on
  • Kidney problems Worth acting on
  • Raised blood pressure Worth acting on
  • Hives Worth acting on

Showing the 10 most notable of 41 label-listed effects — ranked by how unusual each one is across medicines generally, with serious effects weighted up.

From the ADVERSE REACTIONS section of the FDA label for Diltiazem. Read the label on DailyMed › Where a percentage is shown, it is the share of 34,400 voluntary FDA FAERS reports for Diltiazem that mention that effect — a reporting proportion, not an incidence rate and not evidence the drug caused it. Zone Diet’s licensed record lists no adverse effects our clinical vocabulary could match, so there is no Zone Diet side to compare — that is a limit of the record, not a statement that Zone Diet has no side effects.

From our Q&A

Questions About Zone Diet or Diltiazem

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Zone Diet or Diltiazem, 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 Diltiazem

This page covers Zone Diet only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Diltiazem page lists 260 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), Coleus (major) and Grapefruit (major).

By severity: 7 major · 214 moderate · 39 minor.

From our pharmacist’s overview on the Diltiazem page

“Someone on diltiazem (Cardizem, Tiazac) is usually managing blood pressure, angina, or a fast heart rhythm, so this list deserves genuine care. Seven of the 260 ingredients on file carry a major rating, and two of those are things people actually buy: grapefruit, which blocks the enzyme that clears diltiazem and can push its blood leve…”

Reviewed by 2 · Jul 18, 2026

Open the Diltiazem interaction page

How much people look this up

Where Zone Diet and Diltiazem 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 Zone Diet
Steady interest

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

29 days ago today
Medication Diltiazem
Top 10%

#279 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.

Where does our data come from?
  • Source: the Natural Medicines (TRC Healthcare) clinical database — the evidence-graded professional reference for herb & supplement interactions.
  • Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Zone Diet reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Zone Diet and Diltiazem records this page draws on were last updated June 22, 2026.
  • What “no known interaction” means: no documented interaction in the sources above — not a guarantee of safety. Supplements are studied far less than prescription drugs, so we say exactly what the evidence supports, and nothing more.
Data structure & sourcing designed and verified by .
Eating pattern

About Zone Diet

What is Zone Diet?

  • Weight loss
  • Blood sugar control
  • Reducing inflammation
  • Heart health support
  • Improving energy and athletic performance

The Zone Diet is an eating plan, not an herb or supplement, that aims to balance every meal into roughly 40% carbohydrate, 30% protein, and 30% fat. It can help some people lose weight and improve diet quality, mostly by encouraging portion control and lean proteins, but evidence that its specific ratio is better than other balanced diets is limited. Talk with your doctor, pharmacist, or a dietitian before starting, especially if you have a medical condition.

Eating plan (whole-food meals and snacks), meal-delivery services, prepackaged bars and shakes

An interaction check asks whether these two react with each other — it does not ask whether Zone Diet is a good idea for someone in your situation. Here is what our Zone Diet record says about it on its own.

Zone Diet: dosing

There is no pill or standardized "dose" for the Zone Diet because it is an eating pattern, not a supplement. Instead, the plan is followed by structuring meals around the 40% carbohydrate, 30% protein, 30% fat idea and eating regular, portion-controlled meals and snacks.If you use Zone-branded products like bars or meals, follow the label directions.

From our Zone Diet monograph — the full record covers uses, side effects and every documented interaction.

Read the full Zone Diet monograph & all interactions
Medication

About Diltiazem

What Is Diltiazem Used For?

Brand names: Cardizem, Cardizem SR, Diltiaz SR, Cardizem CD, Tiazac, Diltiaz XT, Diltiaz CD, Dilacor, Diltiaz, Cardizem LA, Dilacor XR, Cartia XT, Tiamate, Adizem-SR, Adizem-XL, Angitil SR, Angitil XL, Calcicard CR, Dilcardia SR, Dilzem SR, Dilzem XL, Slozem, Tildiem LA, Tildiem Retard, Viazem XL, Zemtard 120XL, Zemtard 180XL, Zemtard 240XL, Zemtard 300XL

Oral extended-release forms of diltiazem — including Matzim LA, Cardizem LA, Cartia, Cartia XT, Tiadylt ER, and various generic capsules and tablets — are used to treat high blood pressure (hypertension) and chronic stable angina (chest pain brought on by activity). Some capsule formulations, including Cartia, Cartia XT, and certain generics, are also approved for angina due to coronary artery spasm (sudden chest pain caused by a sudden tightening of a coronary artery).

Injectable forms of diltiazem are used in hospital settings to temporarily slow a dangerously fast heart rate in atrial fibrillation or atrial flutter (rapid, irregular heart rhythms), and to restore a normal heart rhythm in paroxysmal supraventricular tachycardia (PSVT) — sudden episodes of a very fast but regular heartbeat originating above the heart's lower chambers.

Most-Reported Side Effects for Diltiazem

From FAERS, the FDA’s public side-effect reporting system (34,400 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Dyspnea 3,309 reports
Fatigue 2,733 reports
Nausea 2,454 reports
Dizziness 2,174 reports
Diarrhea 2,113 reports
See full Diltiazem drug information
Keep checking

Other Drugs & Zone Diet

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

0Major
0Moderate
0Minor
2,829No known interaction
2,829 No interaction
No interaction 2,829 drugs checked — show the list

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

Showing the 60 most looked-up of 2,829 medications checked with no known interaction — see the full Zone Diet list.

See the full Zone Diet interactions page
See every supplement checked against Diltiazem, ranked by severity
Evidence & sources

Zone Diet References

The 4 references that drive our Zone Diet monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

  1. Fontani, G., Corradeschi, F., Felici, A., Alfatti, F., Bugarini, R., Fiaschi, A. I., Cerretani, D., Montorfano, G., Rizzo, A. M., and Berra, B. Blood profiles, body fat and mood state in healthy subjects on different diets supplemented with Omega-3 polyu
  2. Gardner CD, Kiazand A, Alhassan S, et al. Comparison of the Atkins, Zone, Ornish, and LEARN diets for change in weight and related risk factors among overweight premenopausal women: the A TO Z Weight Loss Study: a randomized trial. JAMA. 2007 Mar 7;297(9) PubMed
  3. McAuley KA, Hopkins CM, Smith KJ, et al. Comparison of high-fat and high-protein diets with a high-carbohydrate diet in insulin-resistant obese women. Diabetologia. 2005 Jan;48(1):8-16. Epub 2004 Dec 23. Erratum in: Diabetologia. 2005 May;48(5):1033.
  4. Jarvis M, McNaughton L, Seddon A, Thompson D. The acute 1-week effects of the Zone diet on body composition, blood lipid levels, and performance in recreational endurance athletes. J Strength Cond Res. 2002 Feb;16(1):50-7. DOI

Medication overviews come from MedlinePlus (NIH); supplement label data from the NIH Dietary Supplement Label Database. Content is written and reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

Pharmacist Counseling Corner

Following Zone Diet While Taking Diltiazem: Common Questions

Is it safe to follow Zone Diet while taking Diltiazem?
We do not list a known interaction between Zone Diet and Diltiazem. That does not guarantee the combination is risk-free, so confirm with your pharmacist or doctor — especially if you take other medications or have a health condition.
Does Diltiazem interact with any supplements?
Yes. Diltiazem has documented interactions with 260 supplements in our database — Zone Diet is not one of them. The Diltiazem interaction page linked on this page lists every one, ranked by severity.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Where next

Keep Exploring

Zone Diet monograph Uses, safety profile, and every drug interaction in one place Diltiazem drug information The full plain-English guide to this medication Diltiazem supplement interactions Every supplement checked against Diltiazem, ranked by severity Supplement interaction checker Check any supplement or product against your medications Browse medications A–Z Every drug we’ve checked against herbs & supplements References The 4 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Diltiazem and Zone Diet?

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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.