Drug & supplement interaction

Padang Cassia + Thiotepa

Thiotepa brand names: Thioplex, Tepadina.

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

Padang Cassia has a moderate interaction with Thiotepa. In vitro research shows that a methanol extract of Padang cassia inhibits cytochrome P450 3A4 (CYP3A4) activity.

Read the full interaction report
SeverityModerate
LikelihoodPossible
EvidenceD
What do Severity, Likelihood & Evidence mean?
Know someone taking this? Share
Facebook Post Reddit Email
On this page
Interaction report

Padang Cassia and Thiotepa

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

Moderate

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

Why this applies to Thiotepa

Thiotepa falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES — the group Padang Cassia interacts with.

In vitro research shows that a methanol extract of Padang cassia inhibits cytochrome P450 3A4 (CYP3A4) activity. Theoretically, taking Padang cassia with CYP3A4 substrates might increase the effects and side effects of these substrates.
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 wrinkle with thiotepa: it's actually a prodrug. Your liver's CYP3A4 enzyme helps convert thiotepa into TEPA, an active form that does part of the cancer-fighting work. So the usual rule flips here. Lab studies suggest concentrated Padang cassia (cassia cinnamon) might slow CYP3A4, which could shift how much active drug you form. That makes the net effect hard to predict, and chemo like this already carries serious risks such as low blood counts, infection, nausea, and mouth sores.

Honestly, this is only test-tube evidence, not proof in people, and sprinkling cinnamon on your oatmeal won't matter. But thiotepa is potent cancer treatment, so before taking any concentrated cinnamon supplement, please clear it with your oncologist or pharmacist first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Subehan S, Kadota S, Tezuka Y. In vitro mechanism-based inactivation of cytochrome P450 3A4 by a new constituent of Cinnamomum burmani. Planta Med 2008;74(12):1474-80.

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

Padang Cassia Also Interacts With Other Medications

Padang Cassia has 933 moderate known drug interactions in our database — the Thiotepa one above is one of them. If you take anything else, check it against the full list below.

Moderate 933 No known interaction 1,897 (incl. Thiotepa)
Taking anything else?

Check Another of Your Medications Against Padang Cassia

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

Everything else you take

See Every Supplement That Interacts With Thiotepa

This page covers Padang Cassia only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Thiotepa page lists 146 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 Acerola (moderate).

By severity: 3 major · 102 moderate · 41 minor.

From our pharmacist’s overview on the Thiotepa page

“Thiotepa (Thioplex, Tepadina) is chemotherapy, given for several cancers and to prepare patients for stem cell transplant, so its 146 supplement interactions make up a list to respect rather than skim. Three carry a major rating: grapefruit, St.”

Reviewed by 2 · Jul 18, 2026

Open the Thiotepa interaction page

How much people look this up

Where Padang Cassia and Thiotepa 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 Padang Cassia
Steady interest

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

29 days ago today
Medication Thiotepa
Steady interest

#2,043 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 Padang Cassia

What is Padang Cassia?

  • Adding flavor to food
  • Digestive upset
  • Blood sugar support
  • Antimicrobial purposes
  • Antioxidant support

Padang Cassia is a type of cinnamon (Indonesian or Korintje cinnamon) grown mainly in Indonesia and used widely as a kitchen spice. As a supplement, evidence for health benefits like blood sugar control is limited and mixed, and like other cassia cinnamons it naturally contains coumarin, which can be harmful to the liver in large amounts. Use food amounts freely, but talk to a pharmacist or doctor before taking concentrated cinnamon supplements.

Read the full Padang Cassia monograph & all interactions
Medication

About Thiotepa Injection

What Is Thiotepa Injection Used For?

Brand names: Thioplex, Tepadina

Tepadina (thiotepa) injection is used for several purposes. It treats adenocarcinoma (a type of cancer) of the breast or ovary. It is also used to control malignant effusions — abnormal fluid buildup in body cavities caused by cancer spreading to those areas. For bladder cancer, Tepadina treats superficial papillary carcinoma of the urinary bladder.

Tepadina is also used in pediatric patients with class 3 beta-thalassemia (a severe inherited blood disorder). In those patients, it is given as part of a preparative regimen — a conditioning treatment to reduce the risk of graft rejection before an allogeneic stem cell transplant (a transplant using donor stem cells), alongside the chemotherapy drugs busulfan and cyclophosphamide.

See full Thiotepa Injection drug information
Keep checking

Other Drugs & Padang Cassia

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

0Major
933Moderate
0Minor
1,896No known interaction
933 Moderate 1,896 No interaction
Moderate

933 interactions

Showing 60 of 933 moderate interactions — see all 933 on the Padang Cassia page.

No interaction 1,896 drugs checked — show the list

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

Showing the 60 most looked-up of 1,896 medications checked with no known interaction — see the full Padang Cassia list.

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

Can you take Padang Cassia with Thiotepa?
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 Padang Cassia and Thiotepa 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 Thiotepa and Padang Cassia?

Our pharmacists answer your medication & supplement questions — free.

Ask a pharmacist

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.