Drug & supplement interaction

European Mandrake + Tolvaptan

Tolvaptan brand names: Samsca, Jynarque.

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

European Mandrake has a moderate interaction with Tolvaptan. Theoretically, concurrent use might increase absorption of some drugs because of inhibited gastrointestinal (GI) motility caused by European mandrake.

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

European Mandrake and Tolvaptan

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

Moderate

ORAL DRUGS

Why this applies to Tolvaptan

Tolvaptan falls under ORAL DRUGS — the group European Mandrake interacts with.

Theoretically, concurrent use might increase absorption of some drugs because of inhibited gastrointestinal (GI) motility caused by European mandrake.
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

Let me start with the big one: European mandrake is genuinely toxic, and I'd urge you not to take it in any form. Setting that aside, here's the interaction on file. Mandrake's tropane alkaloids (like atropine and scopolamine) slow down how fast your gut moves things along. When food and pills sit in your digestive tract longer, your body can sometimes absorb a bit more of a drug like tolvaptan.

For tolvaptan, more drug in your system could mean stronger effects: heavier urination, intense thirst, dry mouth, and a real risk of dehydration or shifts in your sodium levels. Keep in mind this concern is theoretical, based on how these chemicals work, not on actual case reports. Please don't change anything on your own. Talk with your pharmacist or doctor first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. McEvoy GK, ed. AHFS Drug Information. Bethesda, MD: American Society of Health-System Pharmacists, 1998.

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

European Mandrake Also Interacts With Other Medications

European Mandrake has 2,041 moderate known drug interactions in our database — the Tolvaptan one above is one of them. If you take anything else, check it against the full list below.

Moderate 2,041 No known interaction 789 (incl. Tolvaptan)
Taking anything else?

Check Another of Your Medications Against European Mandrake

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

Everything else you take

See Every Supplement That Interacts With Tolvaptan

This page covers European Mandrake only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Tolvaptan page lists 145 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 · 104 moderate · 38 minor.

From our pharmacist’s overview on the Tolvaptan page

“People taking tolvaptan (Samsca, Jynarque) for polycystic kidney disease or low blood sodium are on a drug whose blood level depends heavily on one liver enzyme, CYP3A4, and that is exactly where most of these 145 supplements interfere. Grapefruit can drive tolvaptan levels up, St.”

Reviewed by 2 · Jul 18, 2026

Open the Tolvaptan interaction page

How much people look this up

Where European Mandrake and Tolvaptan 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 European Mandrake
Top 25%

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

29 days ago today
Medication Tolvaptan
Top half

#1,079 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 European Mandrake

What is European Mandrake?

European Mandrake
  • Insomnia (traditional)
  • Pain relief (historical)
  • Anxiety or depression (folk use)
  • Gout and aches (traditional)
  • Sedation or anesthesia (historical)

European mandrake is a highly toxic plant from the nightshade family that was used in ancient and medieval times as a sedative and pain reliever. It contains powerful poisons that can cause serious harm or death, and there is no proof it safely treats any condition. We strongly recommend you do not consume mandrake in any form.

Read the full European Mandrake monograph & all interactions
Medication

About Tolvaptan (kidney disease)

What Is Tolvaptan (kidney disease) Used For?

Brand names: Samsca, Jynarque

Tolvaptan (brand name Jynarque) is used to slow the decline of kidney function in adults who have autosomal dominant polycystic kidney disease (ADPKD) — a genetic condition where fluid-filled cysts grow in the kidneys over time, gradually damaging them. It is specifically for people whose disease is at risk of progressing quickly.

It does not cure ADPKD, but it works to slow down how fast the kidneys deteriorate, helping preserve kidney function for longer.

See full Tolvaptan (kidney disease) drug information
Keep checking

Other Drugs & European Mandrake

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

0Major
2,041Moderate
0Minor
788No known interaction
2,041 Moderate 788 No interaction
Moderate

2,041 interactions

Showing 60 of 2,041 moderate interactions — see all 2,041 on the European Mandrake page.

No interaction 788 drugs checked — show the list

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

Showing the 60 most looked-up of 788 medications checked with no known interaction — see the full European Mandrake list.

See the full European Mandrake interactions page
See every supplement checked against Tolvaptan, 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
European Mandrake monograph › Uses, safety, and every drug interaction in one place Tolvaptan supplement interactions › Every supplement checked against Tolvaptan, ranked by severity Tolvaptan (kidney disease) 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 European Mandrake and Tolvaptan Together: Common Questions

Can you take European Mandrake with Tolvaptan?
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 European Mandrake and Tolvaptan 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 Tolvaptan and European Mandrake?

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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.