Drug & supplement interaction

Hordenine + Opicapone

Opicapone brand name: Ongentys.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 20, 2026
The bottom line No known interaction

We found no known interaction between Hordenine and Opicapone 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

Hordenine and Opicapone

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 Opicapone and Hordenine 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.

Hordenine safety at a glance

Hordenine overall Use caution Human safety data is very limited, and it acts as a stimulant.
Pregnancy Avoid No safety data; avoid use during pregnancy.
Breastfeeding Avoid No safety data; avoid while breastfeeding.

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

Still wondering about combining Opicapone and Hordenine? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Opicapone

Interactions in our licensed database are recorded against drug classes, not just single drug names. Opicapone is filed under 3 classifications — dopamine agonists, p-glycoprotein substrates, oral drugs. Hordenine has documented interactions with 3 drug classes — the most serious being monoamine oxidase inhibitors (maois) (moderate), stimulant drugs (moderate) and cytochrome p450 2d6 (cyp2d6) substrates (minor) — and none of Opicapone’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

Hordenine Does Interact With Other Medications

Hordenine has 180 moderate, 149 minor known drug interactions in our database — Opicapone isn’t one of them. If you take anything else, check it against the full list below.

Moderate 180 Minor 149 No known interaction 2,501 (incl. Opicapone)
Taking anything else?

Check Another of Your Medications Against Hordenine

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

What to actually watch for

No Interaction Found — But Data Suggests Hordenine and Opicapone 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. One of them is worth acting on rather than waiting out — marked below.

  • Raised blood pressure Worth acting on Additional detail

    Hordenine

    “No clinical studies have evaluated the safety of hordenine in humans. However, hordenine is structurally similar to the stimulants N-methyltyramine and synephrine, which are found in bitter orange. Theoretically, hordenine may cause stimulant-related side effects similar to these compounds, including tachycardia and hypertension.”

    Hordenine · Natural Medicines adverse-effect record, reported in hypertension.

    1 source cited
    1. 29888. Nelson BC, Putzbach K, Sharpless KE, Sander LC. Mass spectrometric determination of the predominant adrenergic protoalkaloids in bitter orange (Citrus aurantium). J Agric Food Chem 2007;55(24):9769-75. PubMed

    “Hordenine is structurally similar to the stimulants N-methyltyramine and synephrine, which are found in bitter orange. Theoretically, hordenine may cause stimulant-related side effects similar to these compounds, including tachycardia and hypertension. However, this has not been assessed or reported in humans.”

    Hordenine · Natural Medicines adverse-effect record, reported in hypertension.

    1 source cited
    1. 29888. Nelson BC, Putzbach K, Sharpless KE, Sander LC. Mass spectrometric determination of the predominant adrenergic protoalkaloids in bitter orange (Citrus aurantium). J Agric Food Chem 2007;55(24):9769-75. PubMed

    Opicapone

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

Reported for Hordenine but not commonly for Opicapone: a fast or pounding heartbeat.

Effects for Opicapone come from the ADVERSE REACTIONS section of its FDA label; effects for Hordenine come from the Natural Medicines adverse-effect record, quoted above. Where a percentage is shown, it is the share of 2,261 voluntary FDA FAERS reports for Opicapone 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 Opicapone

This page covers Hordenine only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Opicapone page lists 58 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), St. John's Wort (major), Ayahuasca (moderate), Bitter Melon (moderate) and Black Horehound (moderate).

By severity: 2 major · 39 moderate · 17 minor.

From our pharmacist’s overview on the Opicapone page

“If you take opicapone (Ongentys) alongside levodopa for Parkinson's disease, don't skim this page. Two entries can genuinely undercut your treatment: St.”

Reviewed by 2 · Jul 18, 2026

Open the Opicapone interaction page

One more smart check

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

We hold 339 real supplement products containing Hordenine, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Hordenine. Even though Hordenine itself has no known interaction with Opicapone, 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 Hordenine and Opicapone 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 Hordenine
Top 25%

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

29 days ago today
Medication Opicapone
Top 25%

#463 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 Hordenine reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Hordenine and Opicapone 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 Hordenine

What is Hordenine?

Hordenine
  • Energy and stimulation
  • Athletic and workout performance
  • Weight loss/fat burning
  • Focus and mood
  • Appetite control

Hordenine is a natural alkaloid found in barley and some cacti that is marketed as a stimulant for energy, focus, and fat loss, but solid human evidence for these benefits is lacking. Its safety in people has not been well studied, so caution is warranted, and it should be avoided in pregnancy, breastfeeding, and by people with heart conditions.

Alkaloid isolated from plants such as barley sprouts and certain cacti · Capsules, tablets, powders (often in pre-workout and 'fat burner' blends)

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

Hordenine: dosing

There is no established, well-studied dose for hordenine. The amounts found in supplements vary widely, and they have not been tested for safety or effectiveness in proper human trials.If you choose to use a product containing hordenine, follow the label instructions and do not exceed them. Be aware that it is often mixed with caffeine and other stimulants, so the total stimulant load may be higher than it appears.

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

Read the full Hordenine monograph & all interactions
Medication

About Opicapone

What Is Opicapone Used For?

Brand name: Ongentys

Ongentys (opicapone) is used alongside levodopa/carbidopa to treat Parkinson's disease in adults who experience 'off' episodes — periods when medication wears off and Parkinson's symptoms return before the next dose is due.

It is not used alone. Ongentys works as an add-on to help levodopa stay active longer, reducing the time patients spend in these 'off' states.

Most-Reported Side Effects for Opicapone

From FAERS, the FDA’s public side-effect reporting system (2,261 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Hallucination 314 reports
Dyskinesia 306 reports
Fall 258 reports
On and off phenomenon 158 reports
Tremor 143 reports
See full Opicapone drug information
Keep checking

Other Drugs & Hordenine

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

0Major
180Moderate
149Minor
2,500No known interaction
180 Moderate 149 Minor 2,500 No interaction
Moderate

180 interactions

Showing 60 of 180 moderate interactions — see all 180 on the Hordenine page.

Minor

149 interactions

Showing 60 of 149 minor interactions — see all 149 on the Hordenine page.

No interaction 2,500 drugs checked — show the list

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

Showing the 60 most looked-up of 2,500 medications checked with no known interaction — see the full Hordenine list.

See the full Hordenine interactions page
See every supplement checked against Opicapone, ranked by severity
Evidence & sources

Hordenine References

The 3 references that drive our Hordenine 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. Barwell CJ, Basma AN, Lafi MA, Leake LD. Deamination of hordenine by monoamine oxidase and its action on vasa deferentia of the rat. J Pharm Pharmacol 1989;41(6):421-3. PubMed
  2. Nelson BC, Putzbach K, Sharpless KE, Sander LC. Mass spectrometric determination of the predominant adrenergic protoalkaloids in bitter orange (Citrus aurantium). J Agric Food Chem 2007;55(24):9769-75. PubMed
  3. Liu Y, Santillo MF. Cytochrome P450 2D6 and 3A4 enzyme inhibition by amine stimulants in dietary supplements. Drug Test Anal. 2016;8(3-4):307-10. 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 Hordenine and Opicapone Together: Common Questions

Is it safe to take Hordenine with Opicapone?
We do not list a known interaction between Hordenine and Opicapone. 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 Hordenine and Opicapone 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.
How was the Hordenine and Opicapone combination checked?
Interactions in our licensed database are recorded against drug classes. Opicapone is filed under 3 classifications, and Hordenine has documented interactions with 3 drug classes — none of Opicapone'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 Hordenine interact with any other medications?
Yes. Hordenine has 329 documented drug interactions in our database — Opicapone 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 Opicapone interact with any supplements?
Yes. Opicapone has documented interactions with 58 supplements in our database — Hordenine is not one of them. The Opicapone 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

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

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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.