Drug & supplement interaction

Eicosapentaenoic Acid (epa) + Treprostinil

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

Treprostinil falls into 2 drug categories that Eicosapentaenoic Acid (epa) can interact with; the most serious is rated moderate. Theoretically, taking EPA with antihypertensive drugs might increase the risk of hypotension.

Read the full interaction report
SeverityModerate
LikelihoodProbable
Interactions2
EvidenceB
What do Severity, Likelihood & Evidence mean?
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Interaction report

Eicosapentaenoic Acid (epa) and Treprostinil

These two interact in 2 distinct ways. Each one is explained separately below.

Why Are There 2 Interactions?

Eicosapentaenoic Acid (epa) interacts with whole categories of medication. Treprostinil falls into 2 of those categories, so it can interact with Eicosapentaenoic Acid (epa) in 2 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).

Moderate

ANTIHYPERTENSIVE DRUGS

1 of 2

Why this applies to Treprostinil

Treprostinil falls under ANTIHYPERTENSIVE DRUGS — the group Eicosapentaenoic Acid (epa) interacts with.

Theoretically, taking EPA with antihypertensive drugs might increase the risk of hypotension.
Fish oils containing EPA 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 gist for treprostinil (Orenitram): it's a medicine used for pulmonary arterial hypertension, and one of the ways it works is by relaxing and widening blood vessels, which can lower blood pressure. EPA from fish oil can also nudge your blood pressure down a bit. Put the two together and those effects may stack, so you could feel more lightheaded, dizzy, flushed, or headachy, especially when you stand up quickly.

I want to be honest about the strength of this: it's largely theoretical and based on fish oil's mild blood-pressure-lowering, not strong studies in treprostinil specifically. Treprostinil is not a prodrug, so EPA doesn't change how it's activated. Small amounts of fish in food are unlikely to matter; concentrated EPA supplements are more worth a heads-up. Please check with your doctor or pharmacist before adding it.

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. Sacks FM, Hebert P, Appel LJ, et al. Short report: the effect of fish oil on blood pressure and high-density lipoprotein-cholesterol levels in phase I of the trials of hypertension prevention. J Hypertens 1994;12:209-13.
  4. Vandongen R, Mori TA, Burke V, et al. Effects on blood pressure of omega 3 fats in subjects at increased risk of cardiovascular disease. Hypertension 1993;22:371-9. PubMed
Moderate

ANTICOAGULANT/ANTIPLATELET DRUGS

2 of 2

Treprostinil also falls under ANTICOAGULANT/ANTIPLATELET DRUGS.

Theoretically, EPA may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
In human research, taking EPA has been shown to inhibit platelet aggregation.
Severity Moderate Likelihood Possible Evidence B

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 thing to know about treprostinil (Orenitram): it works partly by relaxing blood vessels and by making platelets a little less sticky. EPA from fish oil does something similar on the platelet side, so stacking the two could nudge your blood toward clotting more slowly than usual.

In plain terms, the worry is a slightly higher chance of bruising, nosebleeds, bleeding gums, or bleeding that's slow to stop. This is mostly a theoretical concern, and small amounts of EPA from eating fish are unlikely to cause trouble. Concentrated fish oil supplements are where it matters more. Don't change anything on your own. Just check with your pharmacist or doctor first, especially if you notice any unusual bleeding.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Terano T, Hirai A, Hamazaki T, et al. Effect of oral administration of highly purified eicosapentaenoic acid on platelet function, blood viscosity and red cell deformability in healthy human subjects. Atherosclerosis 1983;46:321-31.. 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

Eicosapentaenoic Acid (epa) Also Interacts With Other Medications

Eicosapentaenoic Acid (epa) has 288 moderate known drug interactions in our database — the Treprostinil one above is among them. If you take anything else, check it against the full list below.

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

Check Another of Your Medications Against Eicosapentaenoic Acid (epa)

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

Everything else you take

See Every Supplement That Interacts With Treprostinil

This page covers Eicosapentaenoic Acid (epa) only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Treprostinil page lists 291 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), Danshen (major) and Piracetam (major).

By severity: 6 major · 258 moderate · 27 minor.

Open the Treprostinil interaction page

How much people look this up

Where Eicosapentaenoic Acid (epa) and Treprostinil 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 Eicosapentaenoic Acid (epa)
Steady interest

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

29 days ago today
Medication Treprostinil
Steady interest

#1,741 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 Eicosapentaenoic Acid (epa)

What is Eicosapentaenoic Acid (epa)?

  • Heart and triglyceride health
  • Inflammation
  • Mood and depression support
  • Joint comfort
  • General omega-3 supplementation

EPA is an omega-3 fatty acid found mostly in fatty fish and fish oil, and it is best known for lowering high triglycerides. It may also help with inflammation and mood in some people, but evidence varies by condition. Talk with your pharmacist or doctor before starting, especially if you take blood thinners or have a fish allergy.

Read the full Eicosapentaenoic Acid (epa) monograph & all interactions
Medication

About Treprostinil

What Is Treprostinil Used For?

Treprostinil treats pulmonary arterial hypertension (PAH; WHO Group 1) — high blood pressure in the arteries of the lungs. Depending on the product and route, it is used to improve exercise ability, delay disease progression, or reduce symptoms tied to physical activity. Remodulin and treprostinil injection products are also indicated for patients who need to transition away from another PAH medicine called epoprostenol.

Tyvaso, Tyvaso DPI, and Yutrepia (inhaled forms) are additionally approved to treat pulmonary hypertension associated with interstitial lung disease (PH-ILD; WHO Group 3) — lung-pressure problems caused by scarring or inflammation in the lung tissue itself. Orenitram (extended-release oral tablet) is specifically indicated to delay disease progression and improve exercise capacity in PAH.

See full Treprostinil drug information
Keep checking

Other Drugs & Eicosapentaenoic Acid (epa)

Browse every other medication we’ve checked against Eicosapentaenoic Acid (epa) — 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 Eicosapentaenoic Acid (epa) page.

No interaction 2,541 drugs checked — show the list

We also checked Eicosapentaenoic Acid (epa) 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 Eicosapentaenoic Acid (epa) list.

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

Can you take Eicosapentaenoic Acid (epa) with Treprostinil?
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.
Why are there 2 interactions listed for Eicosapentaenoic Acid (epa) and Treprostinil?
Treprostinil belongs to more than one drug category, and Eicosapentaenoic Acid (epa) interacts with each of those categories a little differently. We list every one so nothing is missed — your overall risk is driven by the most serious of them.
How serious is the Eicosapentaenoic Acid (epa) and Treprostinil 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

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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.