Drug & supplement interaction

Rauvolfia Vomitoria + Aspirin, Codeine Phosphate, Phenobarbital

Aspirin, Codeine Phosphate, Phenobarbital brand name: Phenaphen.

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

Aspirin, Codeine Phosphate, Phenobarbital falls into 3 drug categories that Rauvolfia Vomitoria can interact with; the most serious is rated moderate. Theoretically, taking Rauvolfia vomitoria might cause additive sedative effects.

Read the full interaction report
SeverityModerate
LikelihoodPossible
Interactions3
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Rauvolfia Vomitoria and Aspirin, Codeine Phosphate, Phenobarbital

These two interact in 3 distinct ways. Each one is explained separately below.

Why Are There 3 Interactions?

Rauvolfia Vomitoria interacts with whole categories of medication. Aspirin, Codeine Phosphate, Phenobarbital falls into 3 of those categories, so it can interact with Rauvolfia Vomitoria in 3 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).

Moderate

CNS DEPRESSANTS

1 of 3

Why this applies to Aspirin, Codeine Phosphate, Phenobarbital

Aspirin, Codeine Phosphate, Phenobarbital falls under CNS DEPRESSANTS — the group Rauvolfia Vomitoria interacts with.

Theoretically, taking Rauvolfia vomitoria might cause additive sedative effects.
Rauvolfia vomitoria has sedative effects in animal research.
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

This combination product mixes aspirin with two ingredients that calm the nervous system: codeine (an opioid pain reliever) and phenobarbital (a barbiturate sedative). Rauvolfia vomitoria has shown sedative effects in animal studies, so on paper, stacking it on top of codeine and phenobarbital could deepen that drowsy feeling. Think more sleepiness, dizziness, slowed thinking, or in stronger cases, slower breathing.

I want to be honest that this is a theoretical concern based on how these things behave, not solid human proof. Still, since two of these three ingredients already make you sleepy, I'd play it safe. Please check with your pharmacist or doctor before pairing them, and never drive until you know how the mix affects you.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Ekong MB, Peter AI, Edagha IA, et al. Rauwolfia vomitoria inhibits olfaction and modifies olfactory bulb cells. Brain Res Bull 2016;124:206-13. PubMed
  2. Amole OO, Yemitan OK, Oshikoya KA. Anticonvulsant activity of Rauvol?a Vomitoria (Afzel). Afr J Pharmacy Pharmacol 2009;3:319-322.
  3. Campbell JI, Mortensen A, Mølgaard P. Tissue lipid lowering-effect of a traditional Nigerian anti-diabetic infusion of Rauwolfia vomitoria foilage and Citrus aurantium fruit. J Ethnopharmacol 2006;104:379-86. PubMed
Moderate

CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES

2 of 3

Aspirin, Codeine Phosphate, Phenobarbital also falls under CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES.

Theoretically, Rauvolfia vomitoria might increase the levels and clinical effects of CYP2D6 substrates.
Rauvolfia vomitoria contains small amounts of the drug yohimbine. In vitro research shows that yohimbine inhibits CYP2D6 enzyme activity.
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 wrinkle with this combo. Your medication contains codeine, which is a prodrug. That means it has to be switched on by a liver enzyme called CYP2D6 to become morphine, which is what actually relieves pain. Rauvolfia vomitoria carries small amounts of yohimbine, and lab studies suggest yohimbine can block CYP2D6. If that enzyme is slowed down, your body may convert less codeine into morphine, so you could get less pain relief than expected.

Keep in mind this is only theoretical, based on test-tube research, so it may not play out in real life. Still, Rauvolfia is a potent plant on its own, and phenobarbital adds sedation, so please check with your pharmacist or doctor before pairing them.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. VandenBrink, B. M., Foti, R. S., Rock, D. A., Wienkers, L. C., and Wahlstrom, J. L. Prediction of CYP2D6 drug interactions from in vitro data: evidence for substrate-dependent inhibition. Drug Metab Dispos. 2012;40(1):47-53. PubMed
Minor

ANTICOAGULANT/ANTIPLATELET DRUGS

3 of 3

Aspirin, Codeine Phosphate, Phenobarbital also falls under ANTICOAGULANT/ANTIPLATELET DRUGS.

Theoretically, combining Rauvolfia vomitoria with antiplatelet or anticoagulant drugs might have additive effects.
Rauvolfia vomitoria contains small amounts of yohimbine. Research in healthy adults shows that taking yohimbine in doses of 8 mg or more seems to inhibit platelet aggregation in vitro by binding to the alpha-2 adrenoceptor. The effects of Rauvolfia vomitoria itself are unclear.
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 piece that matters for this combo product: the aspirin part is the blood thinner. Rauvolfia vomitoria contains a little yohimbine, and in lab studies yohimbine made platelets a bit less sticky. So in theory, pairing it with aspirin could add to aspirin's blood-thinning effect and make easy bruising, nosebleeds, or stomach bleeding a touch more likely.

I want to be straight with you though: this is a theoretical concern based on how these compounds behave, not on real-world cases. The amount of yohimbine in Rauvolfia is small and its true effect is unclear. The bigger reason to be careful is that Rauvolfia is a potent herb on its own. Please run it by your pharmacist or doctor before combining the two.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Mustonen, P., Savola, J., and Lassila, R. Atipamezole, an imidazoline-type alpha(2)-adrenoceptor inhibitor, binds to human platelets and inhibits their adrenaline-induced aggregation more effectively than yohimbine. Thromb.Res 8-1-2000;99(3):231-237.
  2. Berlin, I., Crespo-Laumonnier, B., Cournot, A., Landault, C., Aubin, F., Legrand, J. C., and Puech, A. J. The alpha 2-adrenergic receptor antagonist yohimbine inhibits epinephrine-induced platelet aggregation in healthy subjects. Clin Pharmacol.Ther. 199
  3. Braddock, L., Cowen, P. J., Elliott, J. M., Fraser, S., and Stump, K. Binding of yohimbine and imipramine to platelets in depressive illness. Psychol.Med 1986;16(4):765-773. PubMed
  4. Boon, N. A., Elliott, J. M., Grahame-Smith, D. G., John-Green, T., and Stump, K. A comparison of alpha 2-adrenoreceptor binding characteristics of intact human platelets identified by [3H]-yohimbine and [3H]- dihydroergocryptine. J Auton.Pharmacol 1983;3

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

Rauvolfia Vomitoria Also Interacts With Other Medications

Rauvolfia Vomitoria has 230 major, 522 moderate, 87 minor known drug interactions in our database — the Aspirin, Codeine Phosphate, Phenobarbital one above is among them. If you take anything else, check it against the full list below.

Major 230 Moderate 522 Minor 87 No known interaction 1,991 (incl. Aspirin, Codeine Phosphate, Phenobarbital)
Taking anything else?

Check Another of Your Medications Against Rauvolfia Vomitoria

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

Everything else you take

See Every Supplement That Interacts With Aspirin, Codeine Phosphate, Phenobarbital

This page covers Rauvolfia Vomitoria only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Aspirin, Codeine Phosphate, Phenobarbital page lists 352 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: 1,4-butanediol (major), Activated Charcoal (major), Asarabacca (major), Beer (major) and Danshen (major).

By severity: 12 major · 304 moderate · 36 minor.

From our pharmacist’s overview on the Aspirin, Codeine Phosphate, Phenobarbital page

“Alcohol is the entry I would flag first with Phenaphen (aspirin, codeine phosphate, phenobarbital): beer or wine layered onto codeine and phenobarbital can deepen sedation and, at worst, slow breathing. This medication deserves real caution with supplements.”

Reviewed by 2 · Jul 18, 2026

Open the Aspirin, Codeine Phosphate, Phenobarbital interaction page

One more smart check

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

We hold 17 real supplement products containing Rauvolfia Vomitoria, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Rauvolfia Vomitoria. Your product may carry other ingredients that interact with Aspirin, Codeine Phosphate, Phenobarbital too, on top of Rauvolfia Vomitoria — 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 Rauvolfia Vomitoria and Aspirin, Codeine Phosphate, Phenobarbital 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 Rauvolfia Vomitoria
Steady interest

#1,014 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Aspirin, Codeine Phosphate, Phenobarbital
Top 10%

#211 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 Rauvolfia Vomitoria

What is Rauvolfia Vomitoria?

  • High blood pressure
  • Anxiety and agitation
  • Sleep problems
  • Mental health symptoms (traditional use)
  • Fever and general ailments

Rauvolfia vomitoria is an African shrub whose root contains powerful alkaloids, including reserpine, that have historically been used for high blood pressure and agitation. Because these compounds can strongly affect blood pressure, mood, and the nervous system, the plant can cause serious side effects and is not a casual supplement. Always talk to a doctor or pharmacist before using it.

Read the full Rauvolfia Vomitoria monograph & all interactions
Keep checking

Other Drugs & Rauvolfia Vomitoria

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

230Major
522Moderate
87Minor
1,990No known interaction
230 Major 522 Moderate 87 Minor 1,990 No interaction
Major

230 interactions

Showing 60 of 230 major interactions — see all 230 on the Rauvolfia Vomitoria page.

Moderate

522 interactions

Showing 60 of 522 moderate interactions — see all 522 on the Rauvolfia Vomitoria page.

Minor

87 interactions

Showing 60 of 87 minor interactions — see all 87 on the Rauvolfia Vomitoria page.

No interaction 1,990 drugs checked — show the list

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

Showing the 60 most looked-up of 1,990 medications checked with no known interaction — see the full Rauvolfia Vomitoria list.

See the full Rauvolfia Vomitoria interactions page
See every supplement checked against Aspirin, Codeine Phosphate, Phenobarbital, 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
Rauvolfia Vomitoria monograph › Uses, safety, and every drug interaction in one place Aspirin, Codeine Phosphate, Phenobarbital supplement interactions › Every supplement checked against Aspirin, Codeine Phosphate, Phenobarbital, 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 Rauvolfia Vomitoria and Aspirin, Codeine Phosphate, Phenobarbital Together: Common Questions

Can you take Rauvolfia Vomitoria with Aspirin, Codeine Phosphate, Phenobarbital?
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.
Why are there 3 interactions listed for Rauvolfia Vomitoria and Aspirin, Codeine Phosphate, Phenobarbital?
Aspirin, Codeine Phosphate, Phenobarbital belongs to more than one drug category, and Rauvolfia Vomitoria interacts with each of those categories a little differently. We list every one so nothing is missed — your overall risk is driven by the most serious of them.
How serious is the Rauvolfia Vomitoria and Aspirin, Codeine Phosphate, Phenobarbital 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

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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.