Drug & supplement interaction

Gamma-linolenic Acid (gla) + Macitentan

Macitentan brand name: Opsumit.

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 Gamma-linolenic Acid (gla) and Macitentan 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.

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Interaction report

Gamma-linolenic Acid (gla) and Macitentan

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 Macitentan and Gamma-linolenic Acid (gla) 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.

Gamma-linolenic Acid (gla) safety at a glance

Gamma-linolenic Ac... overall Use caution Usually well tolerated, but quality and source of the oil matter and some people have side effects.
Pregnancy Avoid Not enough safety data; some sources are traditionally avoided in pregnancy, so it is best to avoid.
Breastfeeding Use caution Safety is not well established, so check with your doctor before use.

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

Still wondering about combining Macitentan and Gamma-linolenic Acid (gla)? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Macitentan

Interactions in our licensed database are recorded against drug classes, not just single drug names. Macitentan is filed under 4 classifications — including antihypertensive drugs, hepatotoxic drugs, cytochrome p450 3a4 (cyp3a4) substrates. Gamma-linolenic Acid (gla) has documented interactions with 1 drug class — the most serious being anticoagulant/antiplatelet drugs (moderate) — and none of Macitentan’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

Gamma-linolenic Acid (gla) Does Interact With Other Medications

Gamma-linolenic Acid (gla) has 122 moderate known drug interactions in our database — Macitentan isn’t one of them. If you take anything else, check it against the full list below.

Moderate 122 No known interaction 2,708 (incl. Macitentan)
Taking anything else?

Check Another of Your Medications Against Gamma-linolenic Acid (gla)

Covers the 2,830 medications we’ve checked against Gamma-linolenic Acid (gla). Pick one to open its full report.

What to actually watch for

What Gamma-linolenic Acid (gla) Itself Has Been Linked To

This is not an interaction — nothing below involves Macitentan. It is the side-effect record for Gamma-linolenic Acid (gla) on its own, from the licensed Natural Medicines monograph. If something new turns up after you add Gamma-linolenic Acid (gla), this list is the first place to look. One entry is worth acting on rather than waiting out — marked below.

  • Bleeding or bruising Worth acting on Additional detail

    “Orally, GLA might prolong bleeding time.”

    Gamma-linolenic Acid (gla) · Natural Medicines adverse-effect record, reported in bleeding.

    1 source cited
    1. 1979. Guivernau M, Meza N, Barja P, Roman O. Clinical and experimental study on the long-term effect of dietary gamma-linolenic acid on plasma lipids, platelet aggregation, thromboxane formation, and prostacyclin production. Prostaglandins Leukot Essent Fatty A PubMed
  • Bloating or gas / Stomach upset / Diarrhea / Vomiting / Nausea Additional detail

    “Orally, GLA may cause mild gastrointestinal effects such as dyspepsia, nausea, bloating, vomiting, soft stools, diarrhea, flatulence, and belching.”

    Gamma-linolenic Acid (gla) · Natural Medicines adverse-effect record, reported in diarrhea.

    4 sources cited
    1. 7701. Leventhal LJ, Boyce EG, Zurier RB. Treatment of rheumatoid arthritis with gammalinolenic acid. Ann Intern Med 1993;119:867-73. PubMed
    2. 7702. Zurier RB, Rossetti RG, Jacobson EW, et al. Gamma-linolenic acid treatment of rheumatoid arthritis. A randomized, placebo-controlled trial. Arthritis Rheum 1996;39:1808-17. PubMed
    3. 8926. Keen H, Payan J, Allawi J, et al. Treatment of diabetic neuropathy with gamma-linolenic acid. The gamma-Linolenic Acid Multicenter Trial Group. Diabetes Care 1993;16:8-15.
    4. 107927. Kim JH, Oh YW, Kim DH, Seo BH, Suh HS, Choi YS. A randomized, placebo-controlled trial of gamma linolenic acid as an add-on therapy to minocycline for the treatment of rosacea. Ann Dermatol 2020;32(6):466-72. PubMed

Everything above comes from the Natural Medicines adverse-effect record for Gamma-linolenic Acid (gla) — expand a row for the licensed statement it rests on. We read the ADVERSE REACTIONS section of Macitentan’s FDA label too, and the two lists don’t meaningfully overlap — which is why no Macitentan column appears here.

Overlapping uses

What Macitentan Is Prescribed For, and What Gamma-linolenic Acid (gla) Has Been Studied For

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

Macitentan is prescribed for: Macitentan tablets — sold under the brand name Opsumit — are used to treat pulmonary arterial hypertension (PAH, WHO Group I), a serious condition where the blood pressure in the arteries supplying the lungs is abnormally high. The goal is to slow down how quickly the disease gets worse and to lower the chances of being hospitalized because of it. In clinical studies, it was shown to be effective in adults with mostly moderate-to-severe PAH symptoms. Patients in those studies had PAH caused by unknown or inherited reasons, connective tissue disorders, or congenital heart disease with repaired heart shunts.

Gamma-linolenic Acid (gla) has been studied for:

  • Hypertension studied, not established Gamma-linolenic Acid (gla) has been studied for this. Natural Medicines rates the evidence: Insufficient Reliable Evidence To Rate Read what the research shows

    Gamma-linolenic Acid (gla) for hypertension

    Oral GLA has only been evaluated in combination with other ingredients; its effect when used alone is unclear.

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 Macitentan on your own; if you are taking Gamma-linolenic Acid (gla) for the same health topic, tell your prescriber, especially if the medicine is being adjusted to a target.

Everything else you take

See Every Supplement That Interacts With Macitentan

This page covers Gamma-linolenic Acid (gla) only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Macitentan page lists 253 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), Beer (major) and Grapefruit (major).

By severity: 9 major · 205 moderate · 39 minor.

From our pharmacist’s overview on the Macitentan page

“If you take macitentan (Opsumit) for pulmonary arterial hypertension, study this page rather than skim it. It lists 253 supplement and herbal ingredients, nine rated major.”

Reviewed by 2 · Jul 18, 2026

Open the Macitentan interaction page

How much people look this up

Where Gamma-linolenic Acid (gla) and Macitentan 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 Gamma-linolenic Acid (gla)
Steady interest

#1,383 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Macitentan
Top 10%

#202 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 Gamma-linolenic Acid (gla) reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Gamma-linolenic Acid (gla) and Macitentan 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 Gamma-linolenic Acid (gla)

What is Gamma-linolenic Acid (gla)?

  • Eczema and dry skin
  • Rheumatoid arthritis
  • Diabetic nerve pain
  • PMS and breast pain
  • Menopausal symptoms

Gamma-linolenic acid (GLA) is an omega-6 fatty acid found in oils like evening primrose and borage. It is most studied for skin conditions, joint pain, and nerve pain, but the evidence is mixed and far from conclusive. It is generally well tolerated, but talk with your pharmacist or doctor before starting, especially if you are pregnant, breastfeeding, or take other medicines.

Seed oil (from evening primrose, borage, or black currant seeds) · Capsules, softgels, and oils (evening primrose oil, borage oil, black currant seed oil)

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

Gamma-linolenic Acid (gla): dosing

There is no single official or standardized dose of GLA. The amount of GLA varies depending on the source oil, since evening primrose, borage, and black currant seed oils contain different concentrations.Because products differ so much, the best approach is to follow the directions on the product label and choose a reputable brand. A pharmacist can help you compare products and figure out an appropriate amount for your situation.Do not assume more is better.

From our Gamma-linolenic Acid (gla) monograph — the full record covers uses, side effects and every documented interaction.

Read the full Gamma-linolenic Acid (gla) monograph & all interactions
Medication

About Macitentan

What Is Macitentan Used For?

Brand name: Opsumit

Macitentan tablets — sold under the brand name Opsumit — are used to treat pulmonary arterial hypertension (PAH, WHO Group I), a serious condition where the blood pressure in the arteries supplying the lungs is abnormally high. The goal is to slow down how quickly the disease gets worse and to lower the chances of being hospitalized because of it.

In clinical studies, it was shown to be effective in adults with mostly moderate-to-severe PAH symptoms. Patients in those studies had PAH caused by unknown or inherited reasons, connective tissue disorders, or congenital heart disease with repaired heart shunts.

See full Macitentan drug information
Keep checking

Other Drugs & Gamma-linolenic Acid (gla)

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

0Major
122Moderate
0Minor
2,707No known interaction
122 Moderate 2,707 No interaction
Moderate

122 interactions

Showing 60 of 122 moderate interactions — see all 122 on the Gamma-linolenic Acid (gla) page.

No interaction 2,707 drugs checked — show the list

We also checked Gamma-linolenic Acid (gla) against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,707 medications checked with no known interaction — see the full Gamma-linolenic Acid (gla) list.

See the full Gamma-linolenic Acid (gla) interactions page
See every supplement checked against Macitentan, ranked by severity
Evidence & sources

Gamma-linolenic Acid (gla) References

The 5 references that drive our Gamma-linolenic Acid (gla) 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. Guivernau M, Meza N, Barja P, Roman O. Clinical and experimental study on the long-term effect of dietary gamma-linolenic acid on plasma lipids, platelet aggregation, thromboxane formation, and prostacyclin production. Prostaglandins Leukot Essent Fatty A PubMed
  2. Leventhal LJ, Boyce EG, Zurier RB. Treatment of rheumatoid arthritis with gammalinolenic acid. Ann Intern Med 1993;119:867-73. PubMed
  3. Zurier RB, Rossetti RG, Jacobson EW, et al. Gamma-linolenic acid treatment of rheumatoid arthritis. A randomized, placebo-controlled trial. Arthritis Rheum 1996;39:1808-17. PubMed
  4. Keen H, Payan J, Allawi J, et al. Treatment of diabetic neuropathy with gamma-linolenic acid. The gamma-Linolenic Acid Multicenter Trial Group. Diabetes Care 1993;16:8-15.
  5. Kim JH, Oh YW, Kim DH, Seo BH, Suh HS, Choi YS. A randomized, placebo-controlled trial of gamma linolenic acid as an add-on therapy to minocycline for the treatment of rosacea. Ann Dermatol 2020;32(6):466-72. 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 Gamma-linolenic Acid (gla) and Macitentan Together: Common Questions

Is it safe to take Gamma-linolenic Acid (gla) with Macitentan?
We do not list a known interaction between Gamma-linolenic Acid (gla) and Macitentan. 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.
Are Gamma-linolenic Acid (gla) and Macitentan 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 Gamma-linolenic Acid (gla) in each. That is a conversation for your prescriber, especially if Macitentan is being adjusted to a target.
How was the Gamma-linolenic Acid (gla) and Macitentan combination checked?
Interactions in our licensed database are recorded against drug classes. Macitentan is filed under 4 classifications, and Gamma-linolenic Acid (gla) has documented interactions with 1 drug class — none of Macitentan'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 Gamma-linolenic Acid (gla) interact with any other medications?
Yes. Gamma-linolenic Acid (gla) has 122 documented drug interactions in our database — Macitentan 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 Macitentan interact with any supplements?
Yes. Macitentan has documented interactions with 253 supplements in our database — Gamma-linolenic Acid (gla) is not one of them. The Macitentan 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

Gamma-linolenic Acid (gla) monograph Uses, safety profile, and every drug interaction in one place Macitentan drug information The full plain-English guide to this medication Macitentan supplement interactions Every supplement checked against Macitentan, 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 5 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Macitentan and Gamma-linolenic Acid (gla)?

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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.