Drug & supplement interaction

Nutmeg + Hyoscyamine, Phenobarbital

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

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

Hyoscyamine, Phenobarbital falls into 3 drug categories that Nutmeg can interact with; the most serious is rated moderate. Theoretically, nutmeg might increase the risk of additive sedation when taken with CNS depressants.

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

Nutmeg and Hyoscyamine, Phenobarbital

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

Why Are There 3 Interactions?

Nutmeg interacts with whole categories of medication. Hyoscyamine, Phenobarbital falls into 3 of those categories, so it can interact with Nutmeg 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 Hyoscyamine, Phenobarbital

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

Theoretically, nutmeg might increase the risk of additive sedation when taken with CNS depressants.
Animal studies suggest that nutmeg extracts and several volatile oils in nutmeg, such as methyleugenol, isoeugenol, safrole, myristicin, trimyristin, 1,8-cineole, and geranyl acetate, have sedative effects. One animal study shows that petroleum ether extracts of nutmeg can potentiate the effects of pentobarbital or phenobarbital. However, evidence from other animal research suggests that the nutmeg constituent myristicin can actually reduce sleeping time in rats pretreated with phenobarbital.
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

Your medication pairs hyoscyamine with phenobarbital, and it's the phenobarbital piece that matters here. Phenobarbital is a barbiturate that calms the nervous system, so it already tends to make people feel drowsy, foggy, or slowed down. The concern is simply additive: some compounds in nutmeg have shown sedative effects in lab and animal studies, so in theory, large amounts could pile on top of the drowsiness phenobarbital already causes.

I want to be honest that this is theoretical and the animal data is mixed, with some studies even pointing the other way. The everyday pinch of nutmeg in your food is very unlikely to cause trouble. Concentrated or high "medicinal" doses are a different story and can be dangerous on their own. If you're considering nutmeg supplements, please run it by your pharmacist or doctor first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Sangalli BC, Chiang W. Toxicology of nutmeg abuse. Clin Toxicol 2000;38:671-8. PubMed
  2. Hallstrom H, Thuvander A. Toxicological evaluation of myristicin. Nat Toxins 1997;5:186-92. DOI
  3. Jeong HG, Yun CH. Induction of rat hepatic cytochrome P450 enzymes by myristicin. Biochem Biophys Res Commun 1995;217:966-71. PubMed
  4. Sell AB, Carlini EA. Anesthetic action of methyleugenol and other eugenol derivatives. Pharmacology. 1976;14(4):367-77. PubMed
  5. Fundarò A, Cassone MC. [Action of essential oils of chamomile, cinnamon, absinthium, mace and origanum on operant conditioning behavior of the rat]. Boll Soc Ital Biol Sper. 1980;56(22):2375-80.
  6. Grover JK, Khandkar S, Vats V, Dhunnoo Y, Das D. Pharmacological studies on Myristica fragrans--antidiarrheal, hypnotic, analgesic and hemodynamic (blood pressure) parameters. Methods Find Exp Clin Pharmacol. 2002;24(10):675-80. PubMed
  7. Sherry CJ, Ray LE, Herron RE. The pharmacological effects of the ligroin extract of nutmeg (Myristica fragrans). J Ethnopharmacol. 1982;6(1):61-6.
Moderate

ANTICHOLINERGIC DRUGS

2 of 3

Hyoscyamine, Phenobarbital also falls under ANTICHOLINERGIC DRUGS.

Theoretically, concomitant use of nutmeg and anticholinergic drugs might decrease the effectiveness of either agent.
Animal research suggests that nutmeg extract can inhibit acetylcholinesterase and might increase acetylcholine levels.
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

Let me put this one in plain terms. Your medication combines hyoscyamine, which is an anticholinergic that works by blocking acetylcholine to calm cramping in the gut and bladder, with phenobarbital, a sedative. The concern here is only with the hyoscyamine half. Nutmeg, in animal and lab studies, seems to do the opposite of hyoscyamine, raising acetylcholine levels. So in theory, nutmeg could blunt how well the hyoscyamine works, meaning less relief from stomach cramps or spasms.

Here's the reassuring part: this is theoretical, based on animal data, and normal cooking amounts of nutmeg are very unlikely to matter. Only large medicinal doses, which are unsafe anyway, would be a worry. If you're considering nutmeg supplements, just check with your pharmacist or doctor first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Mukherjee PK, Kumar V, Houghton PJ. Screening of Indian medicinal plants for acetylcholinesterase inhibitory activity. Phytother Res. 2007;21(12):1142-5. PubMed
Moderate

PHENOBARBITAL (Luminal)

3 of 3
Theoretically, nutmeg might increase or decrease the effects and adverse effects of phenobarbital.
Some animal research suggests that myristicin, a constituent of nutmeg, can reduce sleeping time in rats pretreated with phenobarbital. However, other animal research suggests that petroleum ether extract of nutmeg can potentiate the effects of phenobarbital.
Severity Moderate Likelihood Probable Evidence D

Interaction 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..

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the honest picture with this combo. Your medication pairs hyoscyamine with phenobarbital, and the phenobarbital part is the piece nutmeg might bump into. Phenobarbital is a barbiturate, so it's a sedative that calms the body and the nerves. The concern on file is purely theoretical, coming from animal studies, not people. And the animal data actually points in two opposite directions: one study suggested nutmeg shortened phenobarbital's sleep effect, while another suggested it strengthened it.

Because we honestly can't say which way it would go, I wouldn't lose sleep over it. The amount of nutmeg you'd sprinkle into food is unlikely to matter at all. Larger concentrated nutmeg doses can be toxic on their own, so I'd avoid those. Loop in your pharmacist or doctor before adding any nutmeg supplement.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Hallstrom H, Thuvander A. Toxicological evaluation of myristicin. Nat Toxins 1997;5:186-92. DOI
  2. Jeong HG, Yun CH. Induction of rat hepatic cytochrome P450 enzymes by myristicin. Biochem Biophys Res Commun 1995;217:966-71. PubMed
  3. Grover JK, Khandkar S, Vats V, Dhunnoo Y, Das D. Pharmacological studies on Myristica fragrans--antidiarrheal, hypnotic, analgesic and hemodynamic (blood pressure) parameters. Methods Find Exp Clin Pharmacol. 2002;24(10):675-80. 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

Nutmeg Also Interacts With Other Medications

Nutmeg has 527 moderate known drug interactions in our database — the Hyoscyamine, Phenobarbital one above is among them. If you take anything else, check it against the full list below.

Moderate 527 No known interaction 2,303 (incl. Hyoscyamine, Phenobarbital)
Taking anything else?

Check Another of Your Medications Against Nutmeg

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

Everything else you take

See Every Supplement That Interacts With Hyoscyamine, Phenobarbital

This page covers Nutmeg 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 Nutmeg as Part of a Dietary Supplement Product? Check It for Interactions

We hold 182 real supplement products containing Nutmeg, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Nutmeg. Your product may carry other ingredients that interact with Hyoscyamine, Phenobarbital too, on top of Nutmeg — 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 Nutmeg 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 Nutmeg
Top half

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

29 days ago today
Medication Hyoscyamine, Phenobarbital
Top half

#1,365 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 Nutmeg

What is Nutmeg?

Nutmeg
  • Digestive upset
  • Diarrhea
  • Sleep and relaxation
  • Pain and inflammation
  • Flavoring spice

Nutmeg is a popular cooking spice that has long been used in traditional medicine for digestion and other complaints, but there is little solid human research to support its medicinal use. In normal cooking amounts it is generally safe, but larger "medicinal" doses can cause serious poisoning, so it should never be taken in high amounts.

Read the full Nutmeg monograph & all interactions
Keep checking

Other Drugs & Nutmeg

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

0Major
527Moderate
0Minor
2,302No known interaction
527 Moderate 2,302 No interaction
Moderate

527 interactions

Showing 60 of 527 moderate interactions — see all 527 on the Nutmeg page.

No interaction 2,302 drugs checked — show the list

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

Showing the 60 most looked-up of 2,302 medications checked with no known interaction — see the full Nutmeg list.

See the full Nutmeg 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
Nutmeg 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 Nutmeg and Hyoscyamine, Phenobarbital Together: Common Questions

Can you take Nutmeg 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.
Why are there 3 interactions listed for Nutmeg and Hyoscyamine, Phenobarbital?
Hyoscyamine, Phenobarbital belongs to more than one drug category, and Nutmeg 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 Nutmeg 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.