Drug & supplement interaction

Bitter Orange + Olanzapine

Olanzapine brand name: Zyprexa.

Minor Interaction
Medically reviewed by · Updated October 2026
The bottom line Minor

Bitter Orange has a minor interaction with Olanzapine. Theoretically, bitter orange might increase levels of drug metabolized by CYP2D6.

Read the full interaction report
SeverityMinor
LikelihoodPossible
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Bitter Orange and Olanzapine

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

Minor

CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES

Why this applies to Olanzapine

Olanzapine falls under CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES — the group Bitter Orange interacts with.

Theoretically, bitter orange might increase levels of drug metabolized by CYP2D6.
In vitro research shows that octopamine, a constituent of bitter orange, weakly inhibits CYP2D6 enzymes. This effect has not been reported in humans.
Severity Minor 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 for olanzapine (Zyprexa). Your body partly clears this medicine using a liver enzyme called CYP2D6. Bitter orange contains a compound (octopamine) that may slightly slow that enzyme down. In theory, that could let a bit more olanzapine linger in your system, which might mean stronger effects like extra drowsiness, dizziness, or feeling groggy.

That said, I want to be honest about how thin this evidence is. This was only seen in lab dish studies, not in real people, and CYP2D6 is just one of several pathways that handle olanzapine. So the real-world impact is probably small. Olanzapine isn't a prodrug, so it isn't flipped. Still, bitter orange is a stimulant that can raise heart rate and blood pressure, so check with your pharmacist or doctor before combining them.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. 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

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

Bitter Orange Also Interacts With Other Medications

Bitter Orange has 10 major, 878 moderate, 70 minor known drug interactions in our database — the Olanzapine one above is one of them. If you take anything else, check it against the full list below.

Major 10 Moderate 878 Minor 70 No known interaction 1,872 (incl. Olanzapine)
Taking anything else?

Check Another of Your Medications Against Bitter Orange

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

From our Q&A

Questions About Bitter Orange or Olanzapine

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Bitter Orange or Olanzapine, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

Everything else you take

See Every Supplement That Interacts With Olanzapine

This page covers Bitter Orange only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Olanzapine page lists 160 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Indian Snakeroot (major), Lithium (major), Rauvolfia Vomitoria (major) and 1,3-dmaa (moderate).

By severity: 4 major · 118 moderate · 38 minor.

From our pharmacist’s overview on the Olanzapine page

“Olanzapine (Zyprexa) is an antipsychotic prescribed for schizophrenia and bipolar disorder, and adding supplements to it warrants genuine care. Four of the 160 ingredients on file rate major, and those four deserve your attention before anything else: lithium supplements raise the risk of serotonin syndrome, activated charcoal can trap…”

Reviewed by 2 · Jul 18, 2026

Open the Olanzapine interaction page

One more smart check

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

We hold 1,000 real supplement products containing Bitter Orange, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Bitter Orange. Your product may carry other ingredients that interact with Olanzapine too, on top of Bitter Orange — and those would not show on this page. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Bitter Orange and Olanzapine 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 Bitter Orange
Top 25%

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

29 days ago today
Medication Olanzapine
Steady interest

#1,566 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 Bitter Orange

What is Bitter Orange?

Bitter Orange
  • Weight loss
  • Athletic performance and energy
  • Digestive upset
  • Appetite control
  • Aromatherapy for stress (neroli oil)

Bitter orange is a citrus fruit whose extracts contain synephrine, a mild stimulant often added to weight-loss and energy supplements. Evidence that it works for weight loss or performance is limited, and because it can raise heart rate and blood pressure, people with heart problems, high blood pressure, or who are pregnant should avoid it. Talk to your pharmacist or doctor before using it, especially if you take other stimulants.

Read the full Bitter Orange monograph & all interactions
Medication

About Olanzapine

What Is Olanzapine Used For?

Brand name: Zyprexa

Olanzapine is used for schizophrenia and for manic or mixed episodes of bipolar I disorder, including long-term maintenance treatment. It can also be added to lithium or valproate for manic or mixed episodes. Oral olanzapine is approved for adults and for teens ages 13 to 17.

Olanzapine for injection (intramuscular) is used for sudden agitation linked to schizophrenia or bipolar I mania in adults. Zyprexa Relprevv, a long-acting injection, is used only for schizophrenia. Oral olanzapine taken together with fluoxetine is used for depressive episodes of bipolar I disorder, as covered in the Symbyax labeling.

See full Olanzapine drug information
Keep checking

Other Drugs & Bitter Orange

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

10Major
878Moderate
70Minor
1,871No known interaction
10 Major 878 Moderate 70 Minor 1,871 No interaction
Major

10 interactions

Moderate

878 interactions

Showing 60 of 878 moderate interactions — see all 878 on the Bitter Orange page.

Minor

70 interactions

Showing 60 of 70 minor interactions — see all 70 on the Bitter Orange page.

No interaction 1,871 drugs checked — show the list

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

Showing the 60 most looked-up of 1,871 medications checked with no known interaction — see the full Bitter Orange list.

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

Can you take Bitter Orange with Olanzapine?
There is only a minor interaction, which is usually not serious. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Bitter Orange and Olanzapine interaction?
We rate it Minor. This interaction is generally not clinically significant, but it remains worth noting and discussing with your pharmacist.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Still Have a Question About Olanzapine and Bitter Orange?

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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.