Drug & supplement interaction

German Chamomile + Fosphenytoin Sodium

Fosphenytoin Sodium brand name: Sesquient.

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

Fosphenytoin Sodium falls into 2 drug categories that German Chamomile can interact with; the most serious is rated moderate. Theoretically, German chamomile might have additive effects when used with CNS depressants.

Read the full interaction report
SeverityModerate
LikelihoodPossible
Interactions2
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

German Chamomile and Fosphenytoin Sodium

These two interact in 2 distinct ways. Each one is explained separately below.

Why Are There 2 Interactions?

German Chamomile interacts with whole categories of medication. Fosphenytoin Sodium falls into 2 of those categories, so it can interact with German Chamomile in 2 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 2

Why this applies to Fosphenytoin Sodium

Fosphenytoin Sodium falls under CNS DEPRESSANTS — the group German Chamomile interacts with.

Theoretically, German chamomile might have additive effects when used with CNS depressants.
German chamomile has mild sedative effects. Theoretically, concomitant use with drugs with sedative properties can cause additive effects and side effects.
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 gist of it: Fosphenytoin (Sesquient) is a seizure medicine that gets converted in your body into phenytoin. One of phenytoin's common side effects is drowsiness, dizziness, and feeling a bit unsteady on your feet. German chamomile, especially as a strong tea or concentrated supplement, has a mild calming, sleepy effect of its own.

So the concern here is simply additive sleepiness. Put the two together and you might feel more groggy or wobbly than usual. I'll be honest with you, this is a theoretical worry based on lab-level thinking, not strong human data, so it's not a major red flag. An occasional cup of chamomile tea is unlikely to cause trouble. Still, since fosphenytoin needs careful, steady levels, just check with your pharmacist or doctor before using chamomile regularly.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Viola H, Wasowski C, Levi de Stein M, et al. Apigenin, a component of Matricaria recutita flowers, is a central benzodiazepine receptors-ligand with anxiolytic effects. Planta Med 1995;61:213-6.
  2. Avallone R, Zanoli P, Puia G, et al. Pharmacological profile of apigenin, a flavonoid isolated from Matricaria chamomilla. Biochem Pharmacol 2000;59:1387-94. PubMed
  3. Loggia RD, Traversa U, Scarcia V, et al. Depressive effects of Chamomilla recutita (L.) Rausch, tubular flowers, on central nervous system in mice. Pharmacol Res Commun 1982;14(2):153-162. PubMed
Moderate

CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES

2 of 2

Fosphenytoin Sodium also falls under CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES.

Theoretically, German chamomile might inhibit CYP2C9 and increase levels of drugs metabolized by these enzymes.
In vitro evidence shows that German chamomile might inhibit CYP2C9. So far, this interaction has not been reported in humans. However, there might be an increase in the levels of drugs metabolized by CYP2C9 in patients taking German chamomile.
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 connection worth knowing about. Fosphenytoin is quickly turned into phenytoin in your body, and phenytoin is cleared largely by a liver enzyme called CYP2C9. In lab studies (test tube only, not in people yet), German chamomile appears to slow that enzyme down. If that happened in your body, phenytoin could build up a bit higher than expected.

Phenytoin is a narrow therapeutic index drug, meaning the gap between a helpful level and a too-high level is small. Rising levels can cause dizziness, unsteadiness, slurred speech, double vision, or drowsiness. The good news: this is only theoretical right now, and an occasional cup of chamomile tea is unlikely to matter. Still, since the margin is tight, please check with your pharmacist or doctor before using concentrated chamomile supplements.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Ganzera M, Schneider P, Stuppner H. Inhibitory effects of the essential oil of chamomile (Matricaria recutita L.) and its major constituents on human cytochrome P450 enzymes. Life Sci 2006;78(8):856-861. 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

German Chamomile Also Interacts With Other Medications

German Chamomile has 924 moderate, 35 minor known drug interactions in our database — the Fosphenytoin Sodium one above is among them. If you take anything else, check it against the full list below.

Moderate 924 Minor 35 No known interaction 1,871 (incl. Fosphenytoin Sodium)
Taking anything else?

Check Another of Your Medications Against German Chamomile

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

Everything else you take

See Every Supplement That Interacts With Fosphenytoin Sodium

This page covers German Chamomile only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Fosphenytoin Sodium page lists 212 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: 1,4-butanediol (major), American Hellebore (major), Arsenic (major), Beer (major) and Cesium (major).

By severity: 14 major · 179 moderate · 19 minor.

From our pharmacist’s overview on the Fosphenytoin Sodium page

“Fosphenytoin sodium (Sesquient) converts to phenytoin in the body, and phenytoin is unforgiving about blood levels. A little too low invites seizures, a little too high brings toxicity.”

Reviewed by 2 · Jul 18, 2026

Open the Fosphenytoin Sodium interaction page

One more smart check

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

We hold 782 real supplement products containing German Chamomile, each one broken down to its full ingredient list — and combination products often carry several ingredients besides German Chamomile. Your product may carry other ingredients that interact with Fosphenytoin Sodium too, on top of German Chamomile — 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 German Chamomile and Fosphenytoin Sodium 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 German Chamomile
Top 25%

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

29 days ago today
Medication Fosphenytoin Sodium
Top 25%

#335 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 German Chamomile

What is German Chamomile?

German Chamomile
  • Anxiety and stress
  • Sleep and relaxation
  • Digestive upset
  • Skin irritation and inflammation
  • Mouth sores and gum irritation

German chamomile is a widely used herbal remedy taken mainly as a tea for calming, sleep, and digestive complaints. Early research suggests possible benefits for mild anxiety and some skin or digestive issues, but the evidence is limited and most uses are based on tradition rather than strong proof. It is generally well tolerated, but people allergic to ragweed or related plants and those who are pregnant should be cautious.

Read the full German Chamomile monograph & all interactions
Keep checking

Other Drugs & German Chamomile

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

0Major
924Moderate
35Minor
1,870No known interaction
924 Moderate 35 Minor 1,870 No interaction
Moderate

924 interactions

Showing 60 of 924 moderate interactions — see all 924 on the German Chamomile page.

Minor

35 interactions

No interaction 1,870 drugs checked — show the list

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

Showing the 60 most looked-up of 1,870 medications checked with no known interaction — see the full German Chamomile list.

See the full German Chamomile interactions page
See every supplement checked against Fosphenytoin Sodium, 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
German Chamomile monograph › Uses, safety, and every drug interaction in one place Fosphenytoin Sodium supplement interactions › Every supplement checked against Fosphenytoin Sodium, 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 German Chamomile and Fosphenytoin Sodium Together: Common Questions

Can you take German Chamomile with Fosphenytoin Sodium?
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 2 interactions listed for German Chamomile and Fosphenytoin Sodium?
Fosphenytoin Sodium belongs to more than one drug category, and German Chamomile 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 German Chamomile and Fosphenytoin Sodium 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.