Drug & supplement interaction

Aspen + Glycerol Phenylbutyrate

Glycerol Phenylbutyrate brand name: Ravicti.

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 Aspen and Glycerol Phenylbutyrate 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 label for Glycerol Phenylbutyrate states a food rule worth keeping to, and 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.

Know someone taking this? Share
Facebook Post Reddit Email
On this page
Interaction report

Aspen and Glycerol Phenylbutyrate

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 Glycerol Phenylbutyrate and Aspen 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.

Aspen safety at a glance

Aspen overall Use caution It contains aspirin-like salicylates and may cause similar side effects, so use carefully.
Pregnancy Avoid Because of its aspirin-like activity and lack of safety data, it is best avoided during pregnancy.
Breastfeeding Avoid Not enough is known about safety, and salicylates can pass into breast milk, so avoid use.

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

Still wondering about combining Glycerol Phenylbutyrate and Aspen? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Glycerol Phenylbutyrate

Interactions in our licensed database are recorded against drug classes, not just single drug names. Glycerol Phenylbutyrate is filed under a single classification — oral drugs. Aspen has documented interactions with 3 drug classes — the most serious being aspirin (moderate), choline magnesium trisalicylate (trilisate) (moderate) and salsalate (disalcid) (moderate) — and none of Glycerol Phenylbutyrate’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

Aspen Does Interact With Other Medications

Aspen has 39 moderate known drug interactions in our database — Glycerol Phenylbutyrate isn’t one of them. If you take anything else, check it against the full list below.

Moderate 39 No known interaction 2,791 (incl. Glycerol Phenylbutyrate)
Taking anything else?

Check Another of Your Medications Against Aspen

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

What to actually watch for

No Interaction Found — But Data Suggests Aspen and Glycerol Phenylbutyrate 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

    Aspen

    “There is currently a limited amount of information available about the adverse effects of aspen. Aspen contains salicin, a plant salicylate. Theoretically, aspen taken orally may be associated with the adverse effects seen with other salicylates, such as aspirin. Topically, aspen has been associated with allergic dermatitis.”

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

    2 sources cited
    1. 3700. Goodman LS, Gilman A. The Pharmacological Basis of Therapeutics. 5th ed. New York, NY: Macmillan Publ. Co., Inc., 1975.
    2. 101465. Aalto-Korte K, Välimaa J, Henriks-Eckerman ML, Jolanki R. Allergic contact dermatitis from salicyl alcohol and salicylaldehyde in aspen bark (Populus tremula). Contact Dermatitis 2005;52(2):93-5.

    “A case report describes a 58-year-old man who developed allergic contact dermatitis after handling aspen leaves and bark. The rash spread from his hands to his face, trunk, and extremities. He had positive skin patch tests to salicyl alcohol and salicylaldehyde, which are present in aspen as glucosides, such as salicin.”

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

    1 source cited
    1. 101465. Aalto-Korte K, Välimaa J, Henriks-Eckerman ML, Jolanki R. Allergic contact dermatitis from salicyl alcohol and salicylaldehyde in aspen bark (Populus tremula). Contact Dermatitis 2005;52(2):93-5.

    Glycerol Phenylbutyrate

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

Effects for Glycerol Phenylbutyrate come from the ADVERSE REACTIONS section of its FDA label; effects for Aspen come from the Natural Medicines adverse-effect record, quoted above. Where a percentage is shown, it is the share of 1,358 voluntary FDA FAERS reports for Glycerol Phenylbutyrate 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.

How to take them

Some Glycerol Phenylbutyrate Products Have a Food Rule — Aspen Should Not Break It

At least one FDA label for a product containing Glycerol Phenylbutyrate says to take it with food. If you take Aspen on an empty stomach out of habit, keep them separate — and take Glycerol Phenylbutyrate with a meal where the label says to.

This may not be true of your version. Food instructions belong to the product, not the ingredient: two Glycerol Phenylbutyrate products can carry different directions, and extended-release forms often differ from immediate-release ones. The label we read is quoted below — check the directions on your own box or bottle, or ask your pharmacist, for how to take the exact product you were given.

Instruct patients to take glycerol phenylbutyrate oral liquid with food or formula and to administer directly into the mouth via oral syringe.

From the Dosage and Administration section of the FDA label we read for Glycerol Phenylbutyrate — where that label names a specific product, the instruction is that product's. Read the label on DailyMed ›

A food rule is not an interaction — it is about how much of the medicine you absorb. The directions that came with your own product, and your pharmacist, outrank anything on this page.

Everything else you take

See Every Supplement That Interacts With Glycerol Phenylbutyrate

This page covers Aspen only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Glycerol Phenylbutyrate page lists 17 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Coffee Charcoal (moderate), European Mandrake (moderate), Glucomannan (moderate) and Guar Gum (moderate).

By severity: 1 major · 7 moderate · 9 minor.

From our pharmacist’s overview on the Glycerol Phenylbutyrate page

“Ravicti (glycerol phenylbutyrate) pulls ammonia out of the blood in people with urea cycle disorders, so a dose that never gets absorbed is not a small problem, it can let ammonia climb toward dangerous levels. That is why this list deserves real attention even though it is short.”

Reviewed by 2 · Jul 18, 2026

Open the Glycerol Phenylbutyrate interaction page

One more smart check

Taking Aspen as Part of a Dietary Supplement Product? Check It for Interactions

We hold 8 real supplement products containing Aspen, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Aspen. Even though Aspen itself has no known interaction with Glycerol Phenylbutyrate, another ingredient on your label might. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Aspen and Glycerol Phenylbutyrate 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 Aspen
Steady interest

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

29 days ago today
Medication Glycerol Phenylbutyrate
Top 10%

#171 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 Aspen reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 27, 2026. The Aspen and Glycerol Phenylbutyrate 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 Aspen

What is Aspen?

Aspen
  • Joint and muscle pain
  • Arthritis-related discomfort
  • Urinary tract symptoms and prostate issues
  • Mild fever and inflammation
  • Nerve pain (sciatica, neuropathic pain)

Aspen bark and leaf contain salicin, a natural compound related to aspirin, which is why it is traditionally used for pain, fever, and inflammation. Solid human studies are lacking, and because it acts like aspirin it carries similar risks. Talk to your pharmacist or doctor before using it, especially if you are sensitive to aspirin.

Populus tremuloides · Salicaceae · Bark and leaves (sometimes leaf buds) · Capsules, tinctures, liquid extracts, teas, and dried bark; often combined with other herbs

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

Aspen: dosing

There is no well-established, standardized dose for aspen. The amount of salicin in products can vary widely, and many products combine aspen with other herbs.The safest approach is to follow the directions on the specific product label and not exceed the recommended amount.

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

Read the full Aspen monograph & all interactions
Medication

About Glycerol Phenylbutyrate

What Is Glycerol Phenylbutyrate Used For?

Brand name: Ravicti

Glycerol phenylbutyrate oral liquid — available as the brand Ravicti and as a generic — is used for the long-term (chronic) management of urea cycle disorders (UCDs). UCDs are rare inherited conditions where the body cannot properly convert ammonia into urea, causing toxic ammonia levels to build up in the blood and brain.

It is used in patients whose ammonia cannot be controlled by a low-protein diet and/or amino acid supplements alone. It must always be used alongside dietary protein restriction and, in some cases, additional dietary supplements such as essential amino acids, arginine, or citrulline. It is not for treating a sudden, severe spike in ammonia (acute hyperammonemia), and its safety and effectiveness for N-acetylglutamate synthase (NAGS) deficiency have not been established.

See full Glycerol Phenylbutyrate drug information
Keep checking

Other Drugs & Aspen

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

0Major
39Moderate
0Minor
2,790No known interaction
39 Moderate 2,790 No interaction
Moderate

39 interactions

No interaction 2,790 drugs checked — show the list

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

Showing the 60 most looked-up of 2,790 medications checked with no known interaction — see the full Aspen list.

See the full Aspen interactions page
See every supplement checked against Glycerol Phenylbutyrate, ranked by severity
Evidence & sources

Aspen References

The 3 references that drive our Aspen 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. Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.
  2. Goodman LS, Gilman A. The Pharmacological Basis of Therapeutics. 5th ed. New York, NY: Macmillan Publ. Co., Inc., 1975.
  3. Aalto-Korte K, Välimaa J, Henriks-Eckerman ML, Jolanki R. Allergic contact dermatitis from salicyl alcohol and salicylaldehyde in aspen bark (Populus tremula). Contact Dermatitis 2005;52(2):93-5.

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 Aspen and Glycerol Phenylbutyrate Together: Common Questions

Is it safe to take Aspen with Glycerol Phenylbutyrate?
We do not list a known interaction between Aspen and Glycerol Phenylbutyrate. 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 Aspen and Glycerol Phenylbutyrate 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.
Should I take Aspen and Glycerol Phenylbutyrate at the same time of day?
At least one FDA label for a product containing Glycerol Phenylbutyrate says to take it with food. If you take Aspen on an empty stomach out of habit, keep them separate and take Glycerol Phenylbutyrate with a meal where the label says to. Food instructions belong to the product rather than the ingredient — two Glycerol Phenylbutyrate products can differ — so check the directions on your own box. This is about absorption, not an interaction.
How was the Aspen and Glycerol Phenylbutyrate combination checked?
Interactions in our licensed database are recorded against drug classes. Glycerol Phenylbutyrate is filed under 1 classification, and Aspen has documented interactions with 3 drug classes — none of Glycerol Phenylbutyrate'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 Aspen interact with any other medications?
Yes. Aspen has 39 documented drug interactions in our database — Glycerol Phenylbutyrate 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 Glycerol Phenylbutyrate interact with any supplements?
Yes. Glycerol Phenylbutyrate has documented interactions with 17 supplements in our database — Aspen is not one of them. The Glycerol Phenylbutyrate 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

Aspen monograph Uses, safety profile, and every drug interaction in one place Glycerol Phenylbutyrate drug information The full plain-English guide to this medication Glycerol Phenylbutyrate supplement interactions Every supplement checked against Glycerol Phenylbutyrate, 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 Glycerol Phenylbutyrate and Aspen?

Our pharmacists answer your medication & supplement questions — free.

Ask a pharmacist

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.