Drug & supplement interaction

Gamma-linolenic Acid (gla) + Methenamine Hippurate

Methenamine Hippurate brand names: Urex, Hiprex.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 27, 2026
The bottom line No known interaction

We found no known interaction between Gamma-linolenic Acid (gla) and Methenamine Hippurate 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

Gamma-linolenic Acid (gla) and Methenamine Hippurate

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 Methenamine Hippurate 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 Methenamine Hippurate and Gamma-linolenic Acid (gla)? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Methenamine Hippurate

Interactions in our licensed database are recorded against drug classes, not just single drug names. Methenamine Hippurate is filed under 2 classifications — antibiotic drugs, oral drugs. Gamma-linolenic Acid (gla) has documented interactions with 1 drug class — the most serious being anticoagulant/antiplatelet drugs (moderate) — and none of Methenamine Hippurate’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 — Methenamine Hippurate 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. Methenamine Hippurate)
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

No Interaction Found — But Data Suggests Gamma-linolenic Acid (gla) and Methenamine Hippurate May Share Several of the Same Side Effects

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.

  • Nausea / Vomiting reported in 6.6% of FDA reports for Methenamine Hippurate Additional detail

    Gamma-linolenic Acid (gla)

    “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

    Methenamine Hippurate

    Listed in the ADVERSE REACTIONS section of the FDA label for Methenamine Hippurate, and in voluntary FDA adverse-event reports. Read the label on DailyMed ›

Reported for Gamma-linolenic Acid (gla) but not commonly for Methenamine Hippurate: diarrhea, bloating or gas, stomach upset and bleeding or bruising.

Effects for Methenamine Hippurate come from the ADVERSE REACTIONS section of its FDA label; effects for Gamma-linolenic Acid (gla) come from the Natural Medicines adverse-effect record, quoted above. Where a percentage is shown, it is the share of 1,210 voluntary FDA FAERS reports for Methenamine Hippurate 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.

Everything else you take

See Every Supplement That Interacts With Methenamine Hippurate

This page covers Gamma-linolenic Acid (gla) only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Methenamine Hippurate page lists 44 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Bacillus Coagulans (moderate), Bacillus Subtilis (moderate), Bifidobacterium Animalis Subsp. Lactis (moderate) and Bifidobacterium Bifidum (moderate).

By severity: 1 major · 33 moderate · 10 minor.

From our pharmacist’s overview on the Methenamine Hippurate page

“Most people taking methenamine hippurate (Hiprex, Urex) use it daily to prevent repeat urinary tract infections, and many also take probiotics, which is where the bulk of this 44-ingredient list sits. Even so, the page deserves real vigilance, because one entry is rated major.”

Reviewed by 2 · Jul 18, 2026

Open the Methenamine Hippurate interaction page

How much people look this up

Where Gamma-linolenic Acid (gla) and Methenamine Hippurate 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)
Top half

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

29 days ago today
Medication Methenamine Hippurate
Top half

#912 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 27, 2026. The Gamma-linolenic Acid (gla) and Methenamine Hippurate 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 Methenamine

What Is Methenamine Used For?

Brand names: Urex, Hiprex

Methenamine is used to suppress or prevent frequently recurring urinary tract infections (UTIs), including pyelonephritis (kidney infection) and cystitis (bladder infection). It is intended for long-term or ongoing use after another antibiotic has already cleared the active infection — not as a first treatment for a new, acute infection.

Methenamine Mandelate (available as an oral solution and tablet) is also indicated for infected residual urine that can occur with certain neurologic diseases. It is not appropriate as the sole treatment when an infection is causing systemic symptoms like chills and fever.

Most-Reported Side Effects for Methenamine Hippurate

From FAERS, the FDA’s public side-effect reporting system (1,210 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Urinary tract infection 163 reports
Diarrhea 81 reports
Nausea 80 reports
Fall 74 reports
Fatigue 74 reports
See full Methenamine 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 Methenamine Hippurate, 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 Methenamine Hippurate Together: Common Questions

Is it safe to take Gamma-linolenic Acid (gla) with Methenamine Hippurate?
We do not list a known interaction between Gamma-linolenic Acid (gla) and Methenamine Hippurate. 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 Gamma-linolenic Acid (gla) and Methenamine Hippurate have any of the same side effects?
Yes — our sources link each of them separately to 2 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.
How was the Gamma-linolenic Acid (gla) and Methenamine Hippurate combination checked?
Interactions in our licensed database are recorded against drug classes. Methenamine Hippurate is filed under 2 classifications, and Gamma-linolenic Acid (gla) has documented interactions with 1 drug class — none of Methenamine Hippurate'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 — Methenamine Hippurate 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 Methenamine Hippurate interact with any supplements?
Yes. Methenamine Hippurate has documented interactions with 44 supplements in our database — Gamma-linolenic Acid (gla) is not one of them. The Methenamine Hippurate 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 Methenamine drug information The full plain-English guide to this medication Methenamine Hippurate supplement interactions Every supplement checked against Methenamine Hippurate, 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

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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.