Drug & supplement interaction

Ceylon Leadwort + Osilodrostat Phosphate

Osilodrostat Phosphate brand name: Isturisa.

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

Osilodrostat Phosphate falls into 2 drug categories that Ceylon Leadwort can interact with; the most serious is rated moderate. Plumbagin, a constituent of Ceylon leadwort, has been shown to inhibit cytochrome P450 3A4 (CYP3A4) in vitro.

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

Ceylon Leadwort and Osilodrostat Phosphate

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

Why Are There 2 Interactions?

Ceylon Leadwort interacts with whole categories of medication. Osilodrostat Phosphate falls into 2 of those categories, so it can interact with Ceylon Leadwort in 2 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).

Moderate

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

1 of 2

Why this applies to Osilodrostat Phosphate

Osilodrostat Phosphate falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES — the group Ceylon Leadwort interacts with.

Plumbagin, a constituent of Ceylon leadwort, has been shown to inhibit cytochrome P450 3A4 (CYP3A4) in vitro. So far, this interaction has not been reported in humans. Theoretically, Ceylon leadwort might increase the levels of drugs metabolized by CYP3A4. Some drugs metabolized by CYP3A4 include lovastatin (Mevacor), clarithromycin (Biaxin), indinavir (Crixivan), sildenafil (Viagra), triazolam (Halcion), and numerous others.
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

Isturisa (osilodrostat) is partly cleared by a liver enzyme called CYP3A4. The plumbagin in Ceylon Leadwort has been shown to block that enzyme, but only in lab dish studies so far, not in actual people. So this is more of a theoretical heads-up than a proven problem.

If that blocking did happen in the body, your osilodrostat could clear more slowly and build up. Since osilodrostat lowers cortisol, higher levels could push it too far, leading to things like nausea, fatigue, dizziness, low blood pressure, or low potassium showing up on labs. This drug also affects heart rhythm (QT prolongation), so I'd be cautious. The evidence here is weak, but please run it by your doctor or pharmacist before combining them rather than guessing.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Chen A, Zhou X, Tang S, Liu M, Wang X. Evaluation of the inhibition potential of plumbagin against cytochrome P450 using LC-MS/MS and cocktail approach. Sci Rep. 2016 Jun 22;6:28482. PubMed
Moderate

CYTOCHROME P450 2B6 (CYP2B6) SUBSTRATES

2 of 2

Osilodrostat Phosphate also falls under CYTOCHROME P450 2B6 (CYP2B6) SUBSTRATES.

Plumbagin, a constituent of Ceylon leadwort, has been shown to inhibit cytochrome P450 2B6 (CYP2B6) in vitro. So far, this interaction has not been reported in humans. Theoretically, Ceylon leadwort might increase the levels of drugs metabolized by CYP2B6. Drugs that are metabolized by CYP2B6 include ketamine (Ketalar), phenobarbital, orphenadrine (Norflex), secobarbital (Seconal), and dexamethasone (Decadron).
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 with Isturisa (osilodrostat) and Ceylon Leadwort. This supplement contains plumbagin, which in lab dish studies slowed down an enzyme called CYP2B6. Since osilodrostat is partly handled by that same enzyme, the theory is that the supplement could let osilodrostat build up a bit more than usual. More drug in your system could mean a stronger drop in cortisol and more side effects, things like fatigue, nausea, headache, low blood pressure, swelling, or changes in your potassium levels.

I want to be honest about the evidence though, this is only seen in test tubes, not in real people, so it's truly theoretical. Osilodrostat already needs careful monitoring, so don't add Ceylon Leadwort without first checking with your doctor or pharmacist.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Chen A, Zhou X, Tang S, Liu M, Wang X. Evaluation of the inhibition potential of plumbagin against cytochrome P450 using LC-MS/MS and cocktail approach. Sci Rep. 2016 Jun 22;6:28482. 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

Ceylon Leadwort Also Interacts With Other Medications

Ceylon Leadwort has 1,096 moderate known drug interactions in our database — the Osilodrostat Phosphate one above is among them. If you take anything else, check it against the full list below.

Moderate 1,096 No known interaction 1,734 (incl. Osilodrostat Phosphate)
Taking anything else?

Check Another of Your Medications Against Ceylon Leadwort

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

Everything else you take

See Every Supplement That Interacts With Osilodrostat Phosphate

This page covers Ceylon Leadwort only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Osilodrostat Phosphate page lists 148 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Hellebore (major), Arsenic (major), Cesium (major) and Ephedra (major).

By severity: 8 major · 101 moderate · 39 minor.

From our pharmacist’s overview on the Osilodrostat Phosphate page

“If you take osilodrostat phosphate (Isturisa) to bring cortisol down in Cushing's disease, choose your supplements with real care, because eight of the 148 ingredients on file carry a major rating. The bulk of the list, 121 ingredients, touches the CYP3A4 enzyme that clears this drug, so grapefruit can push its level up while St.”

Reviewed by 2 · Jul 18, 2026

Open the Osilodrostat Phosphate interaction page

One more smart check

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

We hold 96 real supplement products containing Ceylon Leadwort, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Ceylon Leadwort. Your product may carry other ingredients that interact with Osilodrostat Phosphate too, on top of Ceylon Leadwort — 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 Ceylon Leadwort and Osilodrostat Phosphate 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 Ceylon Leadwort
Top half

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

29 days ago today
Medication Osilodrostat Phosphate
Top half

#1,311 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 Ceylon Leadwort

What is Ceylon Leadwort?

  • Digestive complaints and poor appetite
  • Skin conditions and wounds (applied to the skin)
  • Joint pain and swelling
  • Traditional 'metabolism-boosting' tonics
  • Antimicrobial folk remedy

Ceylon Leadwort (Plumbago zeylanica) is a plant long used in Ayurvedic and other traditional medicine systems, mainly for digestion, skin problems, and pain. Solid human studies are lacking, and the plant contains plumbagin, a compound that can irritate skin and tissues and may be unsafe in larger amounts. Talk to a pharmacist or doctor before using it, and avoid it in pregnancy.

Read the full Ceylon Leadwort monograph & all interactions
Keep checking

Other Drugs & Ceylon Leadwort

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

0Major
1,096Moderate
0Minor
1,733No known interaction
1,096 Moderate 1,733 No interaction
Moderate

1,096 interactions

Showing 60 of 1,096 moderate interactions — see all 1,096 on the Ceylon Leadwort page.

No interaction 1,733 drugs checked — show the list

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

Showing the 60 most looked-up of 1,733 medications checked with no known interaction — see the full Ceylon Leadwort list.

See the full Ceylon Leadwort interactions page
See every supplement checked against Osilodrostat Phosphate, 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
Ceylon Leadwort monograph › Uses, safety, and every drug interaction in one place Osilodrostat Phosphate supplement interactions › Every supplement checked against Osilodrostat Phosphate, 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 Ceylon Leadwort and Osilodrostat Phosphate Together: Common Questions

Can you take Ceylon Leadwort with Osilodrostat Phosphate?
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 Ceylon Leadwort and Osilodrostat Phosphate?
Osilodrostat Phosphate belongs to more than one drug category, and Ceylon Leadwort 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 Ceylon Leadwort and Osilodrostat Phosphate 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.