Drug & supplement interaction

Acacia Rigidula + Fosaprepitant

Fosaprepitant brand names: Emend Injection, Focinvez.

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

Acacia Rigidula has a moderate interaction with Fosaprepitant. Theoretically, Acacia rigidula products that are adulterated with beta-methylphenylethylamine (BMPEA) might increase the levels of CYP3A4 substrates.

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

Acacia Rigidula and Fosaprepitant

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

Moderate

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

Why this applies to Fosaprepitant

Fosaprepitant falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES — the group Acacia Rigidula interacts with.

Theoretically, Acacia rigidula products that are adulterated with beta-methylphenylethylamine (BMPEA) might increase the levels of CYP3A4 substrates.
In vitro research shows that BMPEA, an adulterant found in many Acacia rigidula products, inhibits CYP3A4 enzyme by 37%.
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 situation with fosaprepitant (Emend Injection), the IV medicine given to help prevent nausea and vomiting from chemotherapy. Some Acacia rigidula products have been found to contain a hidden stimulant called BMPEA. In lab dish testing only, BMPEA slowed down a liver enzyme called CYP3A4 by about a third. Since fosaprepitant is handled by that same enzyme, the theory is that the drug could build up a bit more than expected, which might mean more drowsiness, fatigue, or hiccups.

I want to be honest that this is theoretical and based only on test-tube data, so it may not amount to much in real life. Still, since fosaprepitant is usually given in a clinic, just tell your care team about any supplement you take so they can keep you safe.

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

Acacia Rigidula Also Interacts With Other Medications

Acacia Rigidula has 812 moderate known drug interactions in our database — the Fosaprepitant one above is one of them. If you take anything else, check it against the full list below.

Moderate 812 No known interaction 2,018 (incl. Fosaprepitant)
Taking anything else?

Check Another of Your Medications Against Acacia Rigidula

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

Everything else you take

See Every Supplement That Interacts With Fosaprepitant

This page covers Acacia Rigidula only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Fosaprepitant page lists 141 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Grapefruit (major), St. John's Wort (major), Adrafinil (moderate), African Wild Potato (moderate) and Alkanna (moderate).

By severity: 2 major · 109 moderate · 30 minor.

From our pharmacist’s overview on the Fosaprepitant page

“Fosaprepitant (Emend Injection, Focinvez) is the IV drug that keeps chemotherapy from making you sick, so anything that undercuts it costs you real comfort, and I would treat this list with genuine care before adding a supplement to it. Nearly all 141 entries hinge on one liver enzyme, CYP3A4, and the traffic runs both ways, since some…”

Reviewed by 2 · Jul 18, 2026

Open the Fosaprepitant interaction page

How much people look this up

Where Acacia Rigidula and Fosaprepitant 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 Acacia Rigidula
Steady interest

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

29 days ago today
Medication Fosaprepitant
Steady interest

#2,153 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 Acacia Rigidula

What is Acacia Rigidula?

Acacia Rigidula
  • Weight loss
  • Energy and stimulation
  • Boosting metabolism
  • Appetite control
  • Pre-workout/athletic performance

Acacia rigidula is a shrub from Texas and Mexico that is marketed in weight-loss and energy supplements. There is very little reliable human evidence that it works, and some products have been found to contain an unapproved stimulant drug (BMPEA), which raises real safety concerns. Most people should avoid it and talk to a pharmacist or doctor before trying any product containing it.

Read the full Acacia Rigidula monograph & all interactions
Keep checking

Other Drugs & Acacia Rigidula

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

0Major
812Moderate
0Minor
2,017No known interaction
812 Moderate 2,017 No interaction
Moderate

812 interactions

Showing 60 of 812 moderate interactions — see all 812 on the Acacia Rigidula page.

No interaction 2,017 drugs checked — show the list

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

Showing the 60 most looked-up of 2,017 medications checked with no known interaction — see the full Acacia Rigidula list.

See the full Acacia Rigidula interactions page
See every supplement checked against Fosaprepitant, 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
Acacia Rigidula monograph › Uses, safety, and every drug interaction in one place Fosaprepitant supplement interactions › Every supplement checked against Fosaprepitant, 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 Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking Acacia Rigidula and Fosaprepitant Together: Common Questions

Can you take Acacia Rigidula with Fosaprepitant?
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 Acacia Rigidula and Fosaprepitant 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 Fosaprepitant and Acacia Rigidula?

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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.