Drug & supplement interaction

Magnolia + Hyoscyamine, Phenobarbital

Hyoscyamine, Phenobarbital brand names: Levsin Pb, Levsinex Pb Timecaps.

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

Magnolia has a moderate interaction with Hyoscyamine, Phenobarbital. Theoretically, concomitant use of large doses of magnolia bark and CNS depressants might have additive effects.

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

Magnolia and Hyoscyamine, Phenobarbital

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

Moderate

CNS DEPRESSANTS

Why this applies to Hyoscyamine, Phenobarbital

Hyoscyamine, Phenobarbital falls under CNS DEPRESSANTS — the group Magnolia interacts with.

Theoretically, concomitant use of large doses of magnolia bark and CNS depressants might have additive effects.
In vitro and animal research shows that constituents extracted from magnolia bark, especially honokiol and magnolol, have sedative effects. These effects may be due to the inhibition of catecholamine release and modulation of gamma-aminobutyric acid-A (GABA-A) receptors.
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 pill contains phenobarbital, a barbiturate that calms the brain and central nervous system. Magnolia bark, through its compounds honokiol and magnolol, appears to have its own mild calming effect, likely by nudging the same GABA pathways. So the worry here is that the two could pile on top of each other and leave you more sedated than expected, with possible drowsiness, dizziness, slowed breathing, or trouble staying alert.

I'll be honest about the evidence though: this is only based on lab and animal studies, so it's theoretical and most likely to matter with concentrated magnolia supplement doses, not a sip of tea. Still, since phenobarbital is already strongly sedating, it's worth a quick chat with your pharmacist or doctor before adding magnolia.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Kuribara H, Kishi E, Hattori N, et al. The anxiolytic effect of two oriental herbal drugs in Japan attributed to honokiol from magnolia bark. J Pharm Pharmacol 2000;52:1425-9. PubMed
  2. Tachikawa E, Takahashi M, Kashimoto T. Effects of extract and ingredients isolated from Magnolia obovata thunberg on catecholamine secretion from bovine adrenal chromaffin cells. Biochem Pharmacol 2000;60:433-40. 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

Magnolia Also Interacts With Other Medications

Magnolia has 350 moderate known drug interactions in our database — the Hyoscyamine, Phenobarbital one above is one of them. If you take anything else, check it against the full list below.

Moderate 350 No known interaction 2,480 (incl. Hyoscyamine, Phenobarbital)
Taking anything else?

Check Another of Your Medications Against Magnolia

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

Everything else you take

See Every Supplement That Interacts With Hyoscyamine, Phenobarbital

This page covers Magnolia only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Hyoscyamine, Phenobarbital page lists 164 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), Beer (major), Gamma-hydroxybutyrate (ghb) (major) and Henbane (major).

By severity: 10 major · 134 moderate · 20 minor.

From our pharmacist’s overview on the Hyoscyamine, Phenobarbital page

“The person taking Levsin PB (hyoscyamine with phenobarbital) for gut spasms is often the same person browsing calming herbs and sleep aids, and with this medicine that habit calls for real vigilance. Ten of the 164 supplements on record rate major, and the largest group, 78 ingredients, shares one danger.”

Reviewed by 2 · Jul 18, 2026

Open the Hyoscyamine, Phenobarbital interaction page

One more smart check

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

We hold 736 real supplement products containing Magnolia, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Magnolia. Your product may carry other ingredients that interact with Hyoscyamine, Phenobarbital too, on top of Magnolia — 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 Magnolia and Hyoscyamine, 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 Magnolia
Top 25%

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

29 days ago today
Medication Hyoscyamine, Phenobarbital
Top 25%

#607 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 Magnolia

What is Magnolia?

Magnolia
  • Anxiety and stress
  • Sleep problems
  • Digestive upset
  • Inflammation
  • Nasal congestion and allergies (flower bud)

Magnolia bark and flower buds have a long history in traditional Chinese and Japanese medicine, often for stress, sleep, and digestion. Modern human research is still limited, so we can't be sure how well it works for most uses. Talk with your pharmacist or doctor before trying it, especially if you take other medicines or are pregnant.

Read the full Magnolia monograph & all interactions
Keep checking

Other Drugs & Magnolia

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

0Major
350Moderate
0Minor
2,479No known interaction
350 Moderate 2,479 No interaction
Moderate

350 interactions

Showing 60 of 350 moderate interactions — see all 350 on the Magnolia page.

No interaction 2,479 drugs checked — show the list

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

Showing the 60 most looked-up of 2,479 medications checked with no known interaction — see the full Magnolia list.

See the full Magnolia interactions page
See every supplement checked against Hyoscyamine, 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
Magnolia monograph › Uses, safety, and every drug interaction in one place Hyoscyamine, Phenobarbital supplement interactions › Every supplement checked against Hyoscyamine, 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 Magnolia and Hyoscyamine, Phenobarbital Together: Common Questions

Can you take Magnolia with Hyoscyamine, 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.
How serious is the Magnolia and Hyoscyamine, 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.