Castoreum + Hydroxyurea
Hydroxyurea brand names: Droxia, Hydrea, Siklos, Xromi.
We found no known interaction between Castoreum and Hydroxyurea in our sources. Absence of a documented interaction is not the same as proven safety, and does not guarantee one does not exist. Do not start, stop, or change a medication or supplement based on this page; confirm with your pharmacist or doctor first.
Castoreum and Hydroxyurea
We checked these two against our interaction database. Here is what we found.
No Known Interaction Found
We did not find a documented interaction between Hydroxyurea and Castoreum in our sources. This does not guarantee that the combination is completely free of risk — there is often limited research on supplements and herbal products, especially around drug interactions.
Worth understanding: our licensed dataset holds no drug-interaction record for Castoreum at all — not against Hydroxyurea, and not against any other medication we track. This verdict therefore rests on the absence of any recorded data, not on research that looked at this combination and found nothing. We cannot rule an interaction out.
If you decide to take both, the practical routine is simple: add one new thing at a time and note the date you started it. If the combination is going to disagree with you, it usually shows in the first days to a couple of weeks — and a start date turns “I’ve been feeling off” into something a pharmacist can actually work with. Do not stop a prescribed medicine on your own.
Always talk with your pharmacist or doctor before making changes to your medications or supplements, particularly if you take several medications or have an ongoing health condition.
Castoreum safety at a glance
Safety guidance is general; always confirm with your pharmacist or doctor for your situation.
Questions About Castoreum or Hydroxyurea
These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Castoreum or Hydroxyurea, 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.
See Every Supplement That Interacts With Hydroxyurea
This page covers Castoreum only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Hydroxyurea page lists 18 supplements it has a documented interaction with, worst first, each one explained.
The most serious there right now: Activated Charcoal (major), Coffee Charcoal (moderate), European Mandrake (moderate), Glucomannan (moderate) and Guar Gum (moderate).
By severity: 1 major · 7 moderate · 10 minor.
From our pharmacist’s overview on the Hydroxyurea page
“People take hydroxyurea (Droxia, Hydrea, Siklos, Xromi) for serious reasons, most often sickle cell disease or certain blood cancers, and it only works if a steady dose reaches the bloodstream. That is exactly what nearly all 18 supplements listed here can undermine, so this page earns real vigilance rather than a skim.”
Reviewed by 2 · Jul 18, 2026
Where Castoreum and Hydroxyurea 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.
#1,246 of 1,452 supplements looked up here in the last 7 days
#40 of 2,830 medications looked up here in the last 7 days
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.
Where does our data come from?
- Source: the Natural Medicines (TRC Healthcare) clinical database — the evidence-graded professional reference for herb & supplement interactions. Castoreum is not yet covered by that licensed database, so its write-up cites publicly available medical sources directly (see the references below).
- Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Castoreum reference on this page ↓
- Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Castoreum and Hydroxyurea records this page draws on were last updated June 22, 2026.
- What “no known interaction” means: no documented interaction in the sources above — not a guarantee of safety. Supplements are studied far less than prescription drugs, so we say exactly what the evidence supports, and nothing more.
About Castoreum
What is Castoreum?
- Traditional remedy for menstrual or 'hysteria' complaints
- Folk use for headache and pain
- Flavoring agent (vanilla-like notes)
- Fragrance and perfume ingredient
- Historical use as a sedative or antispasmodic
Castoreum is a brownish, strong-smelling substance taken from the castor sacs of beavers, not a plant. It has a long history in perfumes, flavorings, and folk medicine, but there is no reliable modern evidence that it treats any health condition, so it should not be relied on as a medicine.
Castor sac secretion (castoreum) from beavers, sometimes combined with castor gland and surrounding tissue · Tincture (in traditional and homeopathic medicine), perfume and fragrance ingredient, food flavoring extract
An interaction check asks whether these two react with each other — it does not ask whether Castoreum is a good idea for someone in your situation. Here is what our Castoreum record says about it on its own.
Castoreum: dosing
There is no established or standardized medicinal dose for castoreum. It is not a recognized medicine, and reliable dosing guidelines do not exist.If you encounter a product that contains castoreum (for example, a traditional tincture or homeopathic preparation), follow the directions on the label and do not exceed them.
From our Castoreum monograph — the full record covers uses, side effects and every documented interaction.
About Hydroxyurea
What Is Hydroxyurea Used For?
Brand names: Droxia, Hydrea, Siklos, Xromi
Hydroxyurea is used for several serious conditions. Droxia, Siklos, and Xromi are each indicated to reduce the frequency of painful crises and reduce the need for blood transfusions in patients with sickle cell anemia who have recurrent moderate to severe painful crises. Siklos is approved for adults and children 2 years and older; Xromi is approved for children 6 months and older; Droxia is approved for adults.
Hydrea capsules and Hydroxyurea capsules are indicated for resistant chronic myeloid leukemia and for locally advanced squamous cell carcinomas of the head and neck (excluding the lip) when used together with chemoradiation.
Most-Reported Side Effects for Hydroxyurea
From FAERS, the FDA’s public side-effect reporting system (21,027 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.
Other Drugs & Castoreum
Browse every other medication we’ve checked against Castoreum — both the ones with a known interaction and the ones without. Select any drug for the full detail.
No drugs match “”.
No interaction 2,829 drugs checked — show the list
We also checked Castoreum against these medications and found no known interaction in our sources. Open any page to confirm.
- Apixaban ›
- Levothyroxine ›
- Amlodipine ›
- Methylphenidate ›
- Warfarin ›
- Sertraline ›
- Testosterone ›
- Losartan Potassium ›
- Metoprolol ›
- Aspirin ›
- Ivermectin ›
- Rivaroxaban ›
- Rosuvastatin ›
- Escitalopram ›
- Tadalafil ›
- Acetaminophen ›
- Clopidogrel ›
- Valacyclovir ›
- Atorvastatin ›
- Docusate ›
- Abemaciclib ›
- Methamphetamine ›
- Ibuprofen ›
- Sumatriptan ›
- Semaglutide ›
- Tirzepatide ›
- Warfarin Sodium ›
- Prednisone ›
- Propranolol ›
- Lisdexamfetamine ›
- Acyclovir ›
- Bupropion ›
- Metformin ›
- Amoxicillin ›
- Lisinopril ›
- Bendamustine ›
- Amitriptyline ›
- Doxycycline ›
- Lamotrigine ›
- Fluoxetine ›
- Methotrexate ›
- Acetaminophen, Codeine ›
- Gabapentin ›
- Amphetamine ›
- Pregabalin ›
- Isotretinoin ›
- Dextroamphetamine ›
- Azithromycin ›
- Clonazepam ›
- Quetiapine ›
- Omeprazole ›
- Amlodipine Besylate ›
- Methylene Blue ›
- Duloxetine ›
- Letrozole ›
- Buspirone ›
- Citalopram ›
- Ciprofloxacin ›
- Naproxen ›
- Bisoprolol ›
Showing the 60 most looked-up of 2,829 medications checked with no known interaction — see the full Castoreum list.
Castoreum References
The 3 sources that drive our Castoreum monograph — publicly available pages from reputable medical and government organizations. Every link was verified to work before publishing. Castoreum is not covered by the licensed Natural Medicines interaction database, so its page cites these public sources directly.
- Castoreum (chemical information) — PubChem (NIH National Library of Medicine) Source
- Dietary Supplements: What You Need to Know — NIH Office of Dietary Supplements Source
- Herbal Medicine — MedlinePlus (NIH National Library of Medicine) Source
Medication overviews come from MedlinePlus (NIH); supplement label data from the NIH Dietary Supplement Label Database. Content is written and reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.
Taking Castoreum and Hydroxyurea Together: Common Questions
Is it safe to take Castoreum with Hydroxyurea?
Does Hydroxyurea interact with any supplements?
Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy
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Still Have a Question About Hydroxyurea and Castoreum?
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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.