Drug & supplement interaction

Calanus Oil + 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 20, 2026
The bottom line No known interaction

We found no known interaction between Calanus Oil 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

Calanus Oil 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 Calanus Oil 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.

Worth understanding: our licensed dataset holds no drug-interaction record for Calanus Oil 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.

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.

Calanus Oil safety at a glance

Calanus Oil overall Use caution Generally well tolerated in early studies, but long-term safety data in people are limited.
Pregnancy Avoid There is not enough safety information, so it is best to avoid during pregnancy.
Breastfeeding Avoid Safety during breastfeeding has not been established, so avoid unless your doctor advises otherwise.

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

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

No Interaction Found — But Data Suggests Calanus Oil and Diltiazem May Share a Side Effect

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.

  • A skin rash Additional detail

    Calanus Oil

    “Calanus oil seems to be well tolerated. In one safety study, taking calanus oil for 12 months was reported to cause a higher rate of mild atopic dermatitis (eczema) when compared with placebo.”

    Calanus Oil · Natural Medicines adverse-effect record, reported in dermatitis.

    3 sources cited
    1. 97880. Cook CM, Larsen TS, Derrig LD, Kelly KM, Tande KS. Wax ester rich oil from the marine crustacean, Calanus finmarchicus, is a bioavailable source of EPA and DHA for human consumption. Lipids. 2016;51(10):1137-1144.
    2. 97881. Tande KS, Vo TD, Lynch BS. Clinical safety evaluation of marine oil derived from Calanus finmarchicus. Regul Toxicol Pharmacol. 2016;80:25-31. PubMed
    3. 105408. Dadová K, Petr M, Steffl M, et al. Effect of calanus oil supplementation and 16 week exercise program on selected fitness parameters in older women. Nutrients. 2020 Feb 14;12(2):481. PubMed

    “Orally, calanus oil is associated with more reports of mild atopic dermatitis (eczema) over a 12-month period when compared with placebo.”

    Calanus Oil · Natural Medicines adverse-effect record, reported in dermatitis.

    1 source cited
    1. 97881. Tande KS, Vo TD, Lynch BS. Clinical safety evaluation of marine oil derived from Calanus finmarchicus. Regul Toxicol Pharmacol. 2016;80:25-31. PubMed

    Diltiazem

    Listed in the ADVERSE REACTIONS section of the FDA label for Diltiazem. Read the label on DailyMed ›

Effects for Diltiazem come from the ADVERSE REACTIONS section of its FDA label; effects for Calanus Oil 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.

From our Q&A

Questions About Calanus Oil 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 Calanus Oil 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 Calanus Oil 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 Calanus Oil 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 Calanus Oil
Steady interest

#1,231 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Diltiazem
Top 5%

#134 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 Calanus Oil reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Calanus Oil and Diltiazem records this page draws on were last updated July 10, 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 Calanus Oil

What is Calanus Oil?

  • Heart and metabolic health
  • Source of omega-3 fatty acids
  • Anti-inflammatory support
  • General wellness
  • Exercise and weight management

Calanus oil is a marine omega-3 oil made from a small Arctic zooplankton (Calanus finmarchicus). It is rich in omega-3 fatty acids bound in a unique 'wax ester' form, and early research suggests possible benefits for metabolic and heart health, but the evidence is still preliminary. Talk with your pharmacist or doctor before using it, especially if you have a seafood allergy or are pregnant.

Calanus finmarchicus · Calanidae · Oil extracted from the whole copepod (a tiny marine zooplankton) · Softgel capsules, oil

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

Calanus Oil: dosing

There is no official, standardized dose of calanus oil. Studies have used a fairly small daily amount, often just a gram or two per day, but products and concentrations vary.The best approach is to follow the dose printed on the product label and not exceed it.

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

Read the full Calanus Oil 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 & Calanus Oil

Browse every other medication we’ve checked against Calanus Oil — 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 Calanus Oil 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 Calanus Oil list.

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

Calanus Oil References

The 3 references that drive our Calanus Oil 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. Cook CM, Larsen TS, Derrig LD, Kelly KM, Tande KS. Wax ester rich oil from the marine crustacean, Calanus finmarchicus, is a bioavailable source of EPA and DHA for human consumption. Lipids. 2016;51(10):1137-1144.
  2. Tande KS, Vo TD, Lynch BS. Clinical safety evaluation of marine oil derived from Calanus finmarchicus. Regul Toxicol Pharmacol. 2016;80:25-31. PubMed
  3. Dadová K, Petr M, Steffl M, et al. Effect of calanus oil supplementation and 16 week exercise program on selected fitness parameters in older women. Nutrients. 2020 Feb 14;12(2):481. PubMed

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 Calanus Oil and Diltiazem Together: Common Questions

Is it safe to take Calanus Oil with Diltiazem?
We do not list a known interaction between Calanus Oil 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 Calanus Oil and Diltiazem have any of the same side effects?
Yes — our sources link each of them separately to one 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.
Does Diltiazem interact with any supplements?
Yes. Diltiazem has documented interactions with 260 supplements in our database — Calanus Oil 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

Calanus Oil 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 3 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Diltiazem and Calanus Oil?

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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.