Drug & supplement interaction

Zizyphus + Phenytoin

Phenytoin brand names: Dilantin Kapseals, Dilantin, Di-Phen, Dilantin Infatabs, Phenytek, and others.

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

Zizyphus has a moderate interaction with Phenytoin. Theoretically, zizyphus might cause additive sedative effects when taken with CNS depressants.

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

Zizyphus and Phenytoin

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

Moderate

CNS DEPRESSANTS

Why this applies to Phenytoin

Phenytoin falls under CNS DEPRESSANTS — the group Zizyphus interacts with.

Theoretically, zizyphus might cause additive sedative effects when taken with CNS depressants.
Some animal research has found that various parts of zizyphus have sedative effects. However, other animal research shows that zizyphus plant extract does not alter sleep parameters when used in combination with pentobarbital.
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 simple version: phenytoin (Dilantin) already calms overactive electrical signals in your brain, and it can leave you feeling drowsy, dizzy, or foggy on its own. Zizyphus (jujube) is traditionally used to help with sleep and relaxation, so the concern is that stacking the two together might add up to extra sleepiness or grogginess.

I want to be honest about the strength of this one. It's purely theoretical, based on a few animal studies, and even some of that research showed no real effect on sleep. Eating jujube fruit as a food is unlikely to matter much. A concentrated supplement is the bigger question mark. Since phenytoin is a tricky drug where blood levels matter, please run any zizyphus supplement past your pharmacist or doctor first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Adzu, B., Amos, S., Dzarma, S., Wambebe, C., and Gamaniel, K. Effect of Zizyphus spina-christi Willd aqueous extract on the central nervous system in mice. J Ethnopharmacol. 2002;79(1):13-16.
  2. Morishita, S., Mishima, Y., Hirai, Y., Saito, T., and Shoji, M. Pharmacological studies of water extract of the Zizyphus seed and the Zizyphus seed containing drug. Gen Pharmacol 1987;18(6):637-641. PubMed
  3. Watanabe, I., Saito, H., and Takagi, K. Pharmacological studies of Zizyphus seeds. Jpn J Pharmacol 1973;23(4):563-571. DOI
  4. Wu, S. X., Zhang, J. X., Xu, T., Li, L. F., Zhao, S. Y., and Lan, M. Y. [Effects of seeds, leaves and fruits of Ziziphus spinosa and jujuboside A on central nervous system function]. Zhongguo Zhong Yao Za Zhi 1993;18(11):685-4.
  5. Hajhashemi V, Safaei A. Hypnotic effect of Coriandrum sativum, Ziziphus jujuba, Lavandula angustifolia and Melissa officinalis extracts in mice. Res Pharm Sci. 2015 Nov-Dec;10(6):477-84.

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

Zizyphus Also Interacts With Other Medications

Zizyphus has 468 moderate known drug interactions in our database — the Phenytoin one above is one of them. If you take anything else, check it against the full list below.

Moderate 468 No known interaction 2,362 (incl. Phenytoin)
Taking anything else?

Check Another of Your Medications Against Zizyphus

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

From our Q&A

Questions About Zizyphus or Phenytoin

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Zizyphus or Phenytoin, 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 Phenytoin

This page covers Zizyphus only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Phenytoin page lists 224 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 Kava (major).

By severity: 9 major · 187 moderate · 28 minor.

From our pharmacist’s overview on the Phenytoin page

“Phenytoin (Dilantin) is a seizure medicine with a narrow therapeutic index, meaning small changes in its blood level can bring seizures back or tip over into toxicity, so I treat its supplement list with real seriousness. The biggest group, 78 ingredients, piles on sedation, and alcohol, kava, and GHB all rate major for exactly that re…”

Reviewed by 2 · Jul 18, 2026

Open the Phenytoin interaction page

How much people look this up

Where Zizyphus and Phenytoin 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 Zizyphus
Steady interest

#1,282 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Phenytoin
Steady interest

#1,803 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 Zizyphus

What is Zizyphus?

Zizyphus
  • Sleep problems and insomnia
  • Anxiety and stress
  • Digestive support
  • General nutrition (vitamin C and fiber)
  • Constipation

Zizyphus (jujube) is an edible fruit and traditional remedy used mainly for sleep, anxiety, and digestion. The fruit is a nutritious food, but human evidence for its medicinal benefits is limited and mostly preliminary. If you want to try a supplement form, talk with your pharmacist or doctor first, especially if you are pregnant, breastfeeding, or taking other medicines.

Read the full Zizyphus monograph & all interactions
Medication

About Phenytoin

What Is Phenytoin Used For?

Brand names: Dilantin Kapseals, Dilantin, Di-Phen, Dilantin Infatabs, Phenytek, Dilantin injection

Phenytoin is used to treat and prevent seizures. The specific types covered depend on the formulation. Oral extended-release capsules (including Phenytek), chewable tablets (including Dilantin Infatabs and Phenytoin Infatabs), and oral suspension (including Dilantin-125) are used for tonic-clonic (grand mal) and psychomotor (temporal lobe) seizures; most oral forms also cover prevention and treatment of seizures occurring during or after neurosurgery. Chewable tablets and some capsule formulations also cover complex partial seizures.

Parenteral (injectable) phenytoin sodium is used for generalized tonic-clonic status epilepticus (a prolonged, life-threatening seizure emergency) and for prevention and treatment of seizures during neurosurgery. The IV form can also substitute short-term for oral phenytoin when a patient cannot take it by mouth.

See full Phenytoin drug information
Keep checking

Other Drugs & Zizyphus

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

0Major
468Moderate
0Minor
2,361No known interaction
468 Moderate 2,361 No interaction
Moderate

468 interactions

Showing 60 of 468 moderate interactions — see all 468 on the Zizyphus page.

No interaction 2,361 drugs checked — show the list

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

Showing the 60 most looked-up of 2,361 medications checked with no known interaction — see the full Zizyphus list.

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

Can you take Zizyphus with Phenytoin?
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 Zizyphus and Phenytoin 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 Phenytoin and Zizyphus?

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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.