Drug & supplement interaction

Conjugated Linoleic Acid (cla) + Diltiazem

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

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

Conjugated Linoleic Acid (cla) has a moderate interaction with Diltiazem. Theoretically, taking CLA with antihypertensive drugs might increase the risk of hypotension.

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

Conjugated Linoleic Acid (cla) and Diltiazem

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

Moderate

ANTIHYPERTENSIVE DRUGS

Why this applies to Diltiazem

Diltiazem falls under ANTIHYPERTENSIVE DRUGS — the group Conjugated Linoleic Acid (cla) interacts with.

Theoretically, taking CLA with antihypertensive drugs might increase the risk of hypotension.
Animal research suggests that a particular form of CLA reduces systolic blood pressure. Also, some clinical research shows that CLA enhances the blood pressure-lowering effects of ramipril, an antihypertensive drug.
Severity Moderate Likelihood Possible Evidence A

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: diltiazem already lowers your blood pressure by relaxing your blood vessels. CLA may have a mild blood pressure-lowering effect of its own, so stacking the two could push your numbers down a little more than expected. The clearest signal we have is from a study where CLA boosted the effect of ramipril, a different blood pressure medicine, and we'd expect a similar additive nudge with diltiazem.

If your pressure dips too low, you might feel dizzy, lightheaded, tired, or notice your heartbeat slowing. This isn't a dangerous, must-avoid combo, and the effect is likely small, but it's worth a heads-up to your pharmacist or doctor. Keep an eye on your home blood pressure readings, and don't change your diltiazem on your own.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Nagao, K., Inoue, N., Wang, Y. M., Hirata, J., Shimada, Y., Nagao, T., Matsui, T., and Yanagita, T. The 10trans,12cis isomer of conjugated linoleic acid suppresses the development of hypertension in Otsuka Long-Evans Tokushima fatty rats. Biochem.Biophys PubMed
  2. Zhao, W. S., Zhai, J. J., Wang, Y. H., Xie, P. S., Yin, X. J., Li, L. X., and Cheng, K. L. Conjugated linoleic acid supplementation enhances antihypertensive effect of ramipril in Chinese patients with obesity-related hypertension. Am.J Hypertens. 2009;2 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

Conjugated Linoleic Acid (cla) Also Interacts With Other Medications

Conjugated Linoleic Acid (cla) has 288 moderate known drug interactions in our database — the Diltiazem one above is one of them. If you take anything else, check it against the full list below.

Moderate 288 No known interaction 2,542 (incl. Diltiazem)
Taking anything else?

Check Another of Your Medications Against Conjugated Linoleic Acid (cla)

Covers the 2,830 medications we’ve checked against Conjugated Linoleic Acid (cla). Pick one to open its full report.

From our Q&A

Questions About Conjugated Linoleic Acid (cla) 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 Conjugated Linoleic Acid (cla) 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 Conjugated Linoleic Acid (cla) 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 Conjugated Linoleic Acid (cla) 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 Conjugated Linoleic Acid (cla)
Steady interest

#1,429 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Diltiazem
Top 10%

#218 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 Conjugated Linoleic Acid (cla)

What is Conjugated Linoleic Acid (cla)?

Conjugated Linoleic Acid (cla)
  • Weight loss
  • Improving body composition
  • Sports and muscle support
  • Reducing inflammation
  • General wellness

CLA is a fatty acid found naturally in meat and dairy, and supplements are usually made from safflower oil. While it is popular for fat loss and body composition, research results are mixed and any real-world effect appears small at best. It is likely safe for short-term use in most healthy adults, but talk to your pharmacist or doctor before starting it.

Read the full Conjugated Linoleic Acid (cla) 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.

See full Diltiazem drug information
Keep checking

Other Drugs & Conjugated Linoleic Acid (cla)

Browse every other medication we’ve checked against Conjugated Linoleic Acid (cla) — both the ones with a known interaction and the ones without. Select any drug for the full detail.

0Major
288Moderate
0Minor
2,541No known interaction
288 Moderate 2,541 No interaction
Moderate

288 interactions

Showing 60 of 288 moderate interactions — see all 288 on the Conjugated Linoleic Acid (cla) page.

No interaction 2,541 drugs checked — show the list

We also checked Conjugated Linoleic Acid (cla) against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,541 medications checked with no known interaction — see the full Conjugated Linoleic Acid (cla) list.

See the full Conjugated Linoleic Acid (cla) interactions page
See every supplement checked against Diltiazem, 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
Conjugated Linoleic Acid (cla) monograph › Uses, safety, and every drug interaction in one place Diltiazem supplement interactions › Every supplement checked against Diltiazem, ranked by severity Diltiazem 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 Conjugated Linoleic Acid (cla) and Diltiazem Together: Common Questions

Can you take Conjugated Linoleic Acid (cla) with Diltiazem?
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 Conjugated Linoleic Acid (cla) and Diltiazem 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 Diltiazem and Conjugated Linoleic Acid (cla)?

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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.