Drug & supplement interaction

Cod Liver Oil + Hydrochlorothiazide, Lisinopril

Hydrochlorothiazide, Lisinopril brand names: Zestoretic, Prinzide.

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

Cod Liver Oil has a moderate interaction with Hydrochlorothiazide, Lisinopril. Theoretically, taking cod liver oil with antihypertensive drugs might increase the risk of hypotension.

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

Cod Liver Oil and Hydrochlorothiazide, Lisinopril

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

Moderate

ANTIHYPERTENSIVE DRUGS

Why this applies to Hydrochlorothiazide, Lisinopril

Hydrochlorothiazide, Lisinopril falls under ANTIHYPERTENSIVE DRUGS — the group Cod Liver Oil interacts with.

Theoretically, taking cod liver oil with antihypertensive drugs might increase the risk of hypotension.
Cod liver oil can lower blood pressure and might have additive effects in patients treated with antihypertensives; use with caution.
Severity Moderate Likelihood Probable Evidence B

Interaction 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..

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the simple version: the omega-3s in cod liver oil can nudge your blood pressure down a little on their own. Since Zestoretic (lisinopril with hydrochlorothiazide) is already lowering your blood pressure two different ways, stacking the two together could add up and push your numbers lower than intended.

If that happens, you might feel dizzy, lightheaded, tired, or a bit woozy when you stand up quickly. Honestly, the evidence here is on the weaker side and the effect from cod liver oil is usually mild, so for many people this is no big deal. Still, it's worth a quick chat with your pharmacist or doctor, especially if your pressure already runs low or you notice these symptoms. Don't change anything on your own.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Prisco D, Paniccia R, Bandinelli B, et al. Effect of medium-term supplementation with a moderate dose of n-3 polyunsaturated fatty acids on blood pressure in mild hypertensive patients. Thromb Res 1998;1:105-12.
  2. Toft I, Bonaa KH, Ingebretsen OC, et al. Effects of n-3 polyunsaturated fatty acids on glucose homeostasis and blood pressure in essential hypertension. A randomized, controlled trial. Ann Intern Med 1995;123:911-8.
  3. Jensen T, Stender S, Goldstein K, et al. Partial normalization by dietary cod-liver oil of increased microvascular albumin leakage in patients with insulin-dependent diabetes and albuminuria. N Engl J Med 1989;321:1572-7. 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

Cod Liver Oil Also Interacts With Other Medications

Cod Liver Oil has 374 moderate known drug interactions in our database — the Hydrochlorothiazide, Lisinopril one above is one of them. If you take anything else, check it against the full list below.

Moderate 374 No known interaction 2,456 (incl. Hydrochlorothiazide, Lisinopril)
Taking anything else?

Check Another of Your Medications Against Cod Liver Oil

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

From our Q&A

Questions About Cod Liver Oil or Hydrochlorothiazide, Lisinopril

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Cod Liver Oil or Hydrochlorothiazide, Lisinopril, 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 Hydrochlorothiazide, Lisinopril

This page covers Cod Liver Oil only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Hydrochlorothiazide, Lisinopril page lists 236 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), Asarabacca (major) and Dolomite (major).

By severity: 10 major · 199 moderate · 27 minor.

From our pharmacist’s overview on the Hydrochlorothiazide, Lisinopril page

“I would not add a supplement casually alongside hydrochlorothiazide and lisinopril (Zestoretic, Prinzide). This combination lowers blood pressure with a water pill plus an ACE inhibitor, and most interacting ingredients either drag pressure down too far or push back against the drug, while smaller groups strain the kidneys, drain potas…”

Reviewed by 2 · Jul 18, 2026

Open the Hydrochlorothiazide, Lisinopril interaction page

One more smart check

Taking Cod Liver Oil as Part of a Dietary Supplement Product? Check It for Interactions

We hold 17 real supplement products containing Cod Liver Oil, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Cod Liver Oil. Your product may carry other ingredients that interact with Hydrochlorothiazide, Lisinopril too, on top of Cod Liver Oil — 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 Cod Liver Oil and Hydrochlorothiazide, Lisinopril 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 Cod Liver Oil
Steady interest

#1,175 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Hydrochlorothiazide, Lisinopril
Top 25%

#565 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 Cod Liver Oil

What is Cod Liver Oil?

Cod Liver Oil
  • Source of omega-3 fatty acids
  • Vitamin A and D supplementation
  • Heart health
  • Joint and bone health
  • Reducing inflammation

Cod liver oil supplies omega-3 fatty acids (EPA and DHA) along with vitamins A and D, and is popular for heart, joint, and general health support. Evidence is strongest for its nutrient content, but proof of specific disease benefits is mixed. Because it contains vitamin A, taking too much can be harmful, so check with your pharmacist or doctor before using it.

Read the full Cod Liver Oil monograph & all interactions
Medication

About Lisinopril and Hydrochlorothiazide

What Is Lisinopril and Hydrochlorothiazide Used For?

Brand names: Zestoretic, Prinzide

Lisinopril and hydrochlorothiazide tablets — sold as the brand Zestoretic and as the generic combination — are used to treat high blood pressure (hypertension). Lowering blood pressure reduces the risk of serious cardiovascular events such as stroke and heart attack.

This is a fixed-dose combination product and is not intended as a first-line (initial) treatment for high blood pressure. It is typically prescribed for patients whose blood pressure is not adequately controlled on a single medication alone.

See full Lisinopril and Hydrochlorothiazide drug information
Keep checking

Other Drugs & Cod Liver Oil

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

0Major
374Moderate
0Minor
2,455No known interaction
374 Moderate 2,455 No interaction
Moderate

374 interactions

Showing 60 of 374 moderate interactions — see all 374 on the Cod Liver Oil page.

No interaction 2,455 drugs checked — show the list

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

Showing the 60 most looked-up of 2,455 medications checked with no known interaction — see the full Cod Liver Oil list.

See the full Cod Liver Oil interactions page
See every supplement checked against Hydrochlorothiazide, Lisinopril, 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
Cod Liver Oil monograph › Uses, safety, and every drug interaction in one place Hydrochlorothiazide, Lisinopril supplement interactions › Every supplement checked against Hydrochlorothiazide, Lisinopril, ranked by severity Lisinopril and Hydrochlorothiazide 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 Cod Liver Oil and Hydrochlorothiazide, Lisinopril Together: Common Questions

Can you take Cod Liver Oil with Hydrochlorothiazide, Lisinopril?
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 Cod Liver Oil and Hydrochlorothiazide, Lisinopril 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 Hydrochlorothiazide, Lisinopril and Cod Liver 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.