Drug & supplement interaction

Syrian Rue + Opicapone

Opicapone brand name: Ongentys.

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

Syrian Rue has a moderate interaction with Opicapone. Theoretically, Syrian rue might increase the adverse effects of dopamine agonists.

Read the full interaction report
SeverityModerate
LikelihoodPossible
EvidenceD
What do Severity, Likelihood & Evidence mean?
Know someone taking this? Share
Facebook Post Reddit Email
On this page
Interaction report

Syrian Rue and Opicapone

Here is the interaction we found between these two, with the evidence behind it.

Moderate

DOPAMINE AGONISTS

Why this applies to Opicapone

Opicapone falls under DOPAMINE AGONISTS — the group Syrian Rue interacts with.

Theoretically, Syrian rue might increase the adverse effects of dopamine agonists.
Syrian rue contains the constituent harmine. Animal research shows that harmine increases extracellular dopamine levels. The clinical significance of this effect is unclear.
Severity Moderate Likelihood Possible Evidence D

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 gist with Opicapone (Ongentys): you take it alongside levodopa/carbidopa to keep more dopamine working in your brain so your Parkinson's symptoms don't wear off between doses. Syrian Rue's main compounds (harmine and harmaline) are MAO inhibitors, and MAO is one of the enzymes that normally clears dopamine away. So in theory you'd have two things pushing dopamine activity up at the same time.

When dopamine runs high, you can see more of opicapone's familiar issues, like extra involuntary movements (dyskinesia), nausea, dizziness, low blood pressure when standing, trouble sleeping, or hallucinations. I'll be honest, this is theoretical and based on animal data, not proven in people. Still, Syrian Rue is risky on its own, so please run it by your doctor or pharmacist before mixing anything.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Iurlo, M., Leone, G., Schilstrom, B., Linner, L., Nomikos, G., Hertel, P., Silvestrini, B., and Svensson, H. Effects of harmine on dopamine output and metabolism in rat striatum: role of monoamine oxidase-A inhibition. Psychopharmacology (Berl) 2001;159(1 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

Syrian Rue Also Interacts With Other Medications

Syrian Rue has 1,121 moderate known drug interactions in our database — the Opicapone one above is one of them. If you take anything else, check it against the full list below.

Moderate 1,121 No known interaction 1,709 (incl. Opicapone)
Taking anything else?

Check Another of Your Medications Against Syrian Rue

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

Everything else you take

See Every Supplement That Interacts With Opicapone

This page covers Syrian Rue 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

How much people look this up

Where Syrian Rue 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 Syrian Rue
Steady interest

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

29 days ago today
Medication Opicapone
Top 25%

#562 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 Syrian Rue

What is Syrian Rue?

  • Traditional remedy for digestive complaints
  • Used as a sedative or for mood
  • Antimicrobial and antiparasitic folk use
  • Used as a dye and incense
  • Recreational psychoactive use

Syrian Rue (Peganum harmala) is a traditional plant whose seeds contain potent compounds called harmala alkaloids, including MAO-inhibiting harmine and harmaline. There is little reliable human evidence that it safely treats any condition, and it carries real risks of toxicity, so it is not recommended for self-treatment. Talk to a pharmacist or doctor before considering it.

Read the full Syrian Rue 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.

See full Opicapone drug information
Keep checking

Other Drugs & Syrian Rue

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

0Major
1,121Moderate
0Minor
1,708No known interaction
1,121 Moderate 1,708 No interaction
Moderate

1,121 interactions

Showing 60 of 1,121 moderate interactions — see all 1,121 on the Syrian Rue page.

No interaction 1,708 drugs checked — show the list

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

Showing the 60 most looked-up of 1,708 medications checked with no known interaction — see the full Syrian Rue list.

See the full Syrian Rue interactions page
See every supplement checked against Opicapone, 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
Syrian Rue monograph › Uses, safety, and every drug interaction in one place Opicapone supplement interactions › Every supplement checked against Opicapone, ranked by severity Opicapone 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 Syrian Rue and Opicapone Together: Common Questions

Can you take Syrian Rue with Opicapone?
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.
How serious is the Syrian Rue and Opicapone 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

Still Have a Question About Opicapone and Syrian Rue?

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.