Drug & supplement interaction

Valerian + Tezacaftor, Ivacaftor

Tezacaftor, Ivacaftor brand name: Symdeko.

Minor Interaction
Medically reviewed by · Updated October 2026
The bottom line Minor

Valerian has a minor interaction with Tezacaftor, Ivacaftor. Valerian does not seem to have a clinically relevant effect on levels of drugs metabolized by CYP3A4.

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

Valerian and Tezacaftor, Ivacaftor

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

Minor

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

Why this applies to Tezacaftor, Ivacaftor

Tezacaftor, Ivacaftor falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES — the group Valerian interacts with.

Valerian does not seem to have a clinically relevant effect on levels of drugs metabolized by CYP3A4.
Although some in vitro evidence suggests that valerian extract might inhibit or induce CYP3A4, clinical pharmacokinetic (PK) studies show that valerian does not have a clinically significant effect on the CYP3A4 enzyme. In one PK study, taking valerian 125 mg three times daily for 28 days did not affect metabolism of midazolam, an accepted CYP3A4 probe-substrate. In another PK study, taking valerian 1000 mg (providing about 11 mg valerenic acid) nightly for 14 days modestly increases levels of alprazolam, a CYP3A4 substrate, suggesting mild inhibition of CYP3A4. However, this mild inhibition is unlikely to be clinically relevant.
Severity Minor Likelihood Possible Evidence B

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

Good news here: this pairing is about as low-key as drug interactions get. Both tezacaftor and ivacaftor (Symdeko) are handled by a liver enzyme called CYP3A4. In test-tube studies, valerian looked like it might block that enzyme a little, which in theory could let these medicines build up and nudge up side effects like headache, nausea, dizziness, or stomach upset.

But when researchers actually measured this in people, valerian had no meaningful effect on CYP3A4. At most it caused a very mild slowdown that isn't considered clinically important. So for everyday use, valerian is unlikely to change how Symdeko works for you. Still, since Symdeko is taken with fatty food and is a key part of your cystic fibrosis care, it's worth a quick word with your pharmacist or doctor before adding valerian.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Budzinski JW, Foster BC, Vandenhoek S, Arnason JT. An in vitro evaluation of human cytochrome P450 3A4 inhibition by selected commercial herbal extracts and tinctures. Phytomedicine 2000;7:273-82. PubMed
  2. Lefebvre T, Foster BC, Drouin CE, et al. In vitro activity of commercial valerian root extracts against human cytochrome P450 3A4. J Pharm Pharmaceut Sci 2004;7:265-73.
  3. Donovan JL, DeVane CL, Chavin KD, et al. Multiple night-time doses of valerian (Valeriana officinalis) had minimal effects on CYP3A4 activity and no effect on CYP2D6 activity in healthy volunteers. Drug Metab Dispos 2004;32:1333-6. PubMed
  4. Gurley BJ, Gardner SF, Hubbard MA, et al. In vivo effects of goldenseal, kava kava, black cohosh, and valerian on human cytochrome P450 1A2, 2D6, 2E1, and 3A4/5 phenotypes. Clin Pharmacol Ther 2005;77:415-26. PubMed
  5. Hellum BH, Hu Z, Nilsen OG. The induction of CYP1A2, CYP2D6 and CYP3A4 by six trade herbal products in cultured primary human hepatocytes. Basic Clin Pharmacol Toxicol. 2007 Jan;100:23-30. 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

Valerian Also Interacts With Other Medications

Valerian has 338 moderate, 565 minor known drug interactions in our database — the Tezacaftor, Ivacaftor one above is one of them. If you take anything else, check it against the full list below.

Moderate 338 Minor 565 No known interaction 1,927 (incl. Tezacaftor, Ivacaftor)
Taking anything else?

Check Another of Your Medications Against Valerian

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

From our Q&A

Questions About Valerian or Tezacaftor, Ivacaftor

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

This page covers Valerian only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Tezacaftor, Ivacaftor page lists 138 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Grapefruit (major), St. John's Wort (major), Acacia Rigidula (moderate) and Adrafinil (moderate).

By severity: 3 major · 94 moderate · 41 minor.

From our pharmacist’s overview on the Tezacaftor, Ivacaftor page

“Symdeko (tezacaftor and ivacaftor) treats cystic fibrosis and depends on a steady blood level, which is exactly what most of this list can upset, so it deserves genuine attention. The great majority of these ingredients act on CYP3A4, the liver enzyme that clears the drug.”

Reviewed by 2 · Jul 18, 2026

Open the Tezacaftor, Ivacaftor interaction page

One more smart check

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

We hold 2,185 real supplement products containing Valerian, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Valerian. Your product may carry other ingredients that interact with Tezacaftor, Ivacaftor too, on top of Valerian — 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 Valerian and Tezacaftor, Ivacaftor 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 Valerian
Top 10%

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

29 days ago today
Medication Tezacaftor, Ivacaftor
Top 10%

#164 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 Valerian

What is Valerian?

Valerian
  • Insomnia and poor sleep
  • Anxiety and stress
  • Restlessness
  • Muscle tension or cramps
  • Menstrual discomfort

Valerian is an herb whose root is widely used as a natural sleep aid and for calming nerves. The evidence is mixed and often weak, so it may help some people sleep but does not work reliably for everyone. It is generally well tolerated for short-term use, but talk to your pharmacist or doctor before starting it.

Read the full Valerian monograph & all interactions
Medication

About Tezacaftor and Ivacaftor

What Is Tezacaftor and Ivacaftor Used For?

Brand name: Symdeko

Tezacaftor and ivacaftor (Symdeko) treats cystic fibrosis (CF) in people aged 6 years and older. It is for people who have two copies of the F508del mutation. It is also for people who have at least one other CFTR gene mutation that responds to this medicine.

If your genetic type is unknown, an FDA-cleared CF mutation test is used to check for a CFTR mutation.

See full Tezacaftor and Ivacaftor drug information
Keep checking

Other Drugs & Valerian

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

0Major
338Moderate
565Minor
1,926No known interaction
338 Moderate 565 Minor 1,926 No interaction
Moderate

338 interactions

Showing 60 of 338 moderate interactions — see all 338 on the Valerian page.

Minor

565 interactions

Showing 60 of 565 minor interactions — see all 565 on the Valerian page.

No interaction 1,926 drugs checked — show the list

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

Showing the 60 most looked-up of 1,926 medications checked with no known interaction — see the full Valerian list.

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

Can you take Valerian with Tezacaftor, Ivacaftor?
There is only a minor interaction, which is usually not serious. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Valerian and Tezacaftor, Ivacaftor interaction?
We rate it Minor. This interaction is generally not clinically significant, but it remains worth noting and discussing with your pharmacist.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Still Have a Question About Tezacaftor, Ivacaftor and Valerian?

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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.