Drug & supplement interaction

Propionyl-l-carnitine + Diltiazem

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

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 13, 2026
The bottom line No known interaction

We found no known interaction between Propionyl-l-carnitine 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. Additionally, although there is no interaction, the two are separately associated with some of the same side effects, which would make a new symptom harder to attribute to one or the other.

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Interaction report

Propionyl-l-carnitine 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 Propionyl-l-carnitine in our sources. This does not guarantee that the combination is completely free of risk — there is often limited research on supplements and herbal products, especially around drug interactions.

If you decide to take both, the practical routine is simple: add one new thing at a time and note the date you started it. If the combination is going to disagree with you, it usually shows in the first days to a couple of weeks — and a start date turns “I’ve been feeling off” into something a pharmacist can actually work with. 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.

Propionyl-l-carnitine safety at a glance

Propionyl-l-carnit... overall Use caution Generally well tolerated for short-term use, but talk to a healthcare provider first.
Pregnancy Avoid Safety has not been established, so it is best avoided during pregnancy.
Breastfeeding Avoid Not enough safety data is available, so avoid use while breastfeeding.

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

Still wondering about combining Diltiazem and Propionyl-l-carnitine? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Diltiazem

Interactions in our licensed database are recorded against drug classes, not just single drug names. Diltiazem is filed under 9 classifications — including calcium channel blockers, cytochrome p450 1a2 (cyp1a2) inhibitors, cytochrome p450 3a4 (cyp3a4) inhibitors. Propionyl-l-carnitine has documented interactions with 3 drug classes — the most serious being acenocoumarol (sintrom) (moderate), thyroid hormone (moderate) and warfarin (coumadin) (moderate) — and none of Diltiazem’s classifications are among them.

Classification data comes from our licensed Natural Medicines dataset. A medication can belong to classes beyond those recorded there, so this describes how the check was run — it is not a safety guarantee.

Keep it in perspective

Propionyl-l-carnitine Does Interact With Other Medications

Propionyl-l-carnitine has 19 moderate known drug interactions in our database — Diltiazem isn’t one of them. If you take anything else, check it against the full list below.

Moderate 19 No known interaction 2,811 (incl. Diltiazem)
Taking anything else?

Check Another of Your Medications Against Propionyl-l-carnitine

Covers the 2,830 medications we’ve checked against Propionyl-l-carnitine. Pick one to open its full report.

What to actually watch for

No Interaction Found — But Data Suggests Propionyl-l-carnitine and Diltiazem May Share Several of the Same Side Effects

This is not an interaction. Neither one changes how your body handles the other, and nothing here says they react together. What our sources do show is that each has separately been linked to the effects below — so taking both can make those effects more likely to turn up, and harder to pin on one or the other if they do.

  • Diarrhea / Nausea / Vomiting reported in 7.1% of FDA reports for Diltiazem Additional detail

    Propionyl-l-carnitine

    “Orally, nausea, vomiting, diarrhea, and gastric pain have been reported with propionyl-L-carnitine use.”

    Propionyl-l-carnitine · Natural Medicines adverse-effect record, reported in diarrhea.

    6 sources cited
    1. 1579. Cherchi A, Lai C, Onnis E, et al. Propionyl carnitine in stable effort angina. Cardiovasc Drugs Ther 1990;4:481-6. PubMed
    2. 1580. Bartels GL, Remme WJ, den Hartog FR, et al. Additional anti-ischemic effects of long-term L-propionylcarnitine in anginal patients treated with conventional antianginal therapy. Cardiovasc Drugs Ther 1995;9:749-53.
    3. 1582. Caponnetto S, Canale C, Masperone MA, et al. Efficacy of L-propionylcarnitine treatment in patients with left ventricular dysfunction. Eur Heart J 1994;15:1267-73. PubMed
    4. 12682. Gentile V, Vicini P, Prigiotti G, et al. Preliminary observations on the use of propionyl-L-carnitine in combination with sildenafil in patients with erectile dysfunction and diabetes. Curr Med Res Opin 2004;20:1377-84. PubMed
    5. 94439. Brass EP, Koster D, Hiatt WR, Amato A. A systematic review and meta-analysis of propionyl-L-carnitine effects on exercise performance in patients with claudication. Vasc Med 2013;18:3-12.
    6. 94443. Hiatt WR, Creager MA, Amato A, Brass EP. Effect of propionyl-L-carnitine on a background of monitored exercise in patients with claudication secondary to peripheral artery disease. J Cardiopulm Rehabil Prev 2011;31:125-32. PubMed

    Diltiazem

    Listed in the ADVERSE REACTIONS section of the FDA label for Diltiazem, and in voluntary FDA adverse-event reports. Read the label on DailyMed ›

Reported for Propionyl-l-carnitine but not commonly for Diltiazem: back pain.

Effects for Diltiazem come from the ADVERSE REACTIONS section of its FDA label; effects for Propionyl-l-carnitine come from the Natural Medicines adverse-effect record, quoted above. 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. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

Overlapping uses

What Diltiazem Is Prescribed For, and What Propionyl-l-carnitine Has Been Studied For

These two come up together because they touch the same health topic — not because they do the same job. Diltiazem is a prescription medicine with approved uses on its FDA label. Propionyl-l-carnitine is a supplement: what follows is what researchers have looked at it for, and how strong that evidence is.

Diltiazem is prescribed for: 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.

Propionyl-l-carnitine has been studied for:

  • Angina Natural Medicines rates the evidence for Propionyl-l-carnitine: Possibly Effective Read what the research shows

    Propionyl-l-carnitine for angina

    Oral propionyl-L-carnitine may improve myocardial ischemia and exercise capacity in patients with chronic, stable angina.

Effectiveness ratings and the research summaries above are the verbatim record from the Natural Medicines database, which grades evidence from “Effective” down to “Insufficient Reliable Evidence To Rate”. A rating below the top of that scale means researchers have looked at it — not that it works, and never that it can stand in for a prescribed medicine. Do not stop or replace Diltiazem on your own; if you are taking Propionyl-l-carnitine for the same health topic, tell your prescriber, especially if the medicine is being adjusted to a target.

From our Q&A

Questions About Propionyl-l-carnitine 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 Propionyl-l-carnitine 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 Propionyl-l-carnitine 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

One more smart check

Taking Propionyl-l-carnitine as Part of a Dietary Supplement Product? Check It for Interactions

We hold 57 real supplement products containing Propionyl-l-carnitine, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Propionyl-l-carnitine. Even though Propionyl-l-carnitine itself has no known interaction with Diltiazem, another ingredient on your label might. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Propionyl-l-carnitine 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 Propionyl-l-carnitine
Steady interest

#1,251 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Diltiazem
Top 10%

#226 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 Propionyl-l-carnitine reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Propionyl-l-carnitine and Diltiazem records this page draws on were last updated July 11, 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 .
Supplement

About Propionyl-l-carnitine

What is Propionyl-l-carnitine?

  • Peripheral artery disease and leg pain
  • Heart and circulation support
  • Energy and exercise performance
  • Erectile dysfunction
  • Diabetic nerve pain

Propionyl-l-carnitine is a form of the amino acid derivative carnitine that the body uses to help turn fat into energy, and it is studied mostly for circulation problems like peripheral artery disease. Some evidence suggests it may help walking distance in people with poor leg circulation, but results are mixed and it is not a substitute for standard medical care. Talk to a pharmacist or doctor before using it, especially if you have a medical condition or take other medicines.

Capsules, tablets, oral powder

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

Propionyl-l-carnitine: dosing

There is no single official dose of PLC for supplement use, and the right amount can depend on the condition being studied and the specific product. They can help you decide whether PLC is appropriate for you and what amount makes sense.Do not assume more is better. Higher doses raise the chance of side effects without guaranteeing more benefit.

From our Propionyl-l-carnitine monograph — the full record covers uses, side effects and every documented interaction.

Read the full Propionyl-l-carnitine 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 & Propionyl-l-carnitine

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

0Major
19Moderate
0Minor
2,810No known interaction
19 Moderate 2,810 No interaction
Moderate

19 interactions

No interaction 2,810 drugs checked — show the list

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

Showing the 60 most looked-up of 2,810 medications checked with no known interaction — see the full Propionyl-l-carnitine list.

See the full Propionyl-l-carnitine interactions page
See every supplement checked against Diltiazem, ranked by severity
Evidence & sources

Propionyl-l-carnitine References

The 12 references that drive our Propionyl-l-carnitine 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. Cherchi A, Lai C, Onnis E, et al. Propionyl carnitine in stable effort angina. Cardiovasc Drugs Ther 1990;4:481-6. PubMed
  2. Bartels GL, Remme WJ, den Hartog FR, et al. Additional anti-ischemic effects of long-term L-propionylcarnitine in anginal patients treated with conventional antianginal therapy. Cardiovasc Drugs Ther 1995;9:749-53.
  3. Caponnetto S, Canale C, Masperone MA, et al. Efficacy of L-propionylcarnitine treatment in patients with left ventricular dysfunction. Eur Heart J 1994;15:1267-73. PubMed
  4. Benvenga S, Ruggeri RM, Russo A, et al. Usefulness of L-carnitine, a naturally occurring peripheral antagonist of thyroid hormone action, in iatrogenic hyperthyroidism: a randomized, double-blind, placebo-controlled clinical trial. J Clin Endocrinol Meta
  5. Martinez E, Domingo P, Roca-Cusachs A. Potentiation of acenocoumarol action by L-carnitine. J Intern Med 1993;233:94.
  6. Bachmann HU, Hoffmann A. Interaction of food supplement L-carnitine with oral anticoagulant acenocoumarol. Swiss Med Wkly 2004;134:385. PubMed
  7. Gentile V, Vicini P, Prigiotti G, et al. Preliminary observations on the use of propionyl-L-carnitine in combination with sildenafil in patients with erectile dysfunction and diabetes. Curr Med Res Opin 2004;20:1377-84. PubMed
  8. 12761 Benvenga S, Amato A, Calvani M, Trimarchi F. Effects of carnitine on thyroid hormone action. Ann N Y Acad Sci 2004;1033:158-67. PubMed
  9. Brass EP, Koster D, Hiatt WR, Amato A. A systematic review and meta-analysis of propionyl-L-carnitine effects on exercise performance in patients with claudication. Vasc Med 2013;18:3-12.
  10. Hiatt WR, Creager MA, Amato A, Brass EP. Effect of propionyl-L-carnitine on a background of monitored exercise in patients with claudication secondary to peripheral artery disease. J Cardiopulm Rehabil Prev 2011;31:125-32. PubMed
  11. Jacobs PL, Goldstein ER, Blackburn W, et al. Glycine propionyl-L-carnitine produces enhanced anaerobic work capacity with reduced lactate accumulation in resistance trained males. J Int Soc Sports Nutr 2009;6:9. PubMed
  12. Jacobs PL, Goldstein ER. Long-term glycine propionyl-l-carnitine supplementation and paradoxical effects on repeated anaerobic sprint performance. J Int Soc Sports Nutr 2010;7:35.

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

Taking Propionyl-l-carnitine and Diltiazem Together: Common Questions

Is it safe to take Propionyl-l-carnitine with Diltiazem?
We do not list a known interaction between Propionyl-l-carnitine 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.
Do Propionyl-l-carnitine and Diltiazem have any of the same side effects?
Yes — our sources link each of them separately to 3 of the same effects. That is not an interaction: neither changes how your body handles the other. It does mean that if one of those effects turns up, it can be harder to tell which one is behind it. They are listed on this page with the source behind each.
Are Propionyl-l-carnitine and Diltiazem used for the same thing?
They overlap in purpose, which usually means the real question is whether you need both rather than whether they are safe together. This page lists the shared uses and how strong the evidence is for Propionyl-l-carnitine in each. That is a conversation for your prescriber, especially if Diltiazem is being adjusted to a target.
How was the Propionyl-l-carnitine and Diltiazem combination checked?
Interactions in our licensed database are recorded against drug classes. Diltiazem is filed under 9 classifications, and Propionyl-l-carnitine has documented interactions with 3 drug classes — none of Diltiazem's classifications are among them. A medication can belong to classes beyond those recorded in our dataset, so this describes how the check was run rather than guaranteeing safety.
Does Propionyl-l-carnitine interact with any other medications?
Yes. Propionyl-l-carnitine has 19 documented drug interactions in our database — Diltiazem is simply not one of them. If you take anything else, it is worth checking each one; they are all listed on this page.
Does Diltiazem interact with any supplements?
Yes. Diltiazem has documented interactions with 260 supplements in our database — Propionyl-l-carnitine 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

Propionyl-l-carnitine 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 12 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

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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.