Key points
- Hydroxyurea is a capsule that reduces the making of blood cells; your doctor adjusts the dose based on blood tests [1].
- In chronic myeloid leukaemia, it brings a high white count down until targeted treatment starts [3].
- In high-risk thrombocythaemia, it lowered the risk of blood clots [2].
- Regular blood tests are needed; the dose is lowered with kidney failure [1].
What is this drug and how does it work?
Hydroxyurea slows DNA production in rapidly dividing cells and lowers blood cell and platelet counts [1].
For physicians
Inhibits ribonucleotide reductase and stops DNA synthesis in S phase [1].
Which cancers is it used for?
For physicians
How it is taken and dosing
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Swallow the capsule whole with water and do not open it; anyone handling the capsules (especially a pregnant woman) should wear gloves or wash their hands afterwards [1]. The dose is set by weight and blood tests.
For physicians
Standard dosing (FDA label)
Hydroxyurea
By diseaseCycle length: Daily
By disease
| Drug | Dose | Route | Schedule |
|---|---|---|---|
| Hydroxyurea | Individualised by disease, response and blood counts (actual or ideal weight, whichever is lower) | Oral | Daily |
Creatinine clearance below 60 mL/min: reduce the dose by 50%. Blood counts before starting and regularly; stop with severe myelosuppression [1].
Doses follow the trial protocol, guideline or official drug label (source given in the notes of each regimen). Before prescribing, check blood counts, renal and hepatic function, drug interactions and the patient’s condition, and adjust the dose according to the drug label.
Side effects
The most common side effects: low blood counts, nausea, diarrhoea or constipation, mouth sores, and changes in the skin and nails [1].
For physicians
Myelosuppression (leucopenia first), gastrointestinal symptoms, skin changes, macrocytosis [1].
Serious side effects
Serious side effects: very low blood counts, skin ulcers (especially on the lower legs) and, with long-term use, skin cancer [1].
For physicians
When should I call my doctor?
- Fever or signs of infection
- Bleeding or bruising
- A skin sore that does not heal
- A new change in a mole or the skin
Interactions, pregnancy and precautions
- Vaccines: do not have live vaccines [1].
- Skin: protect yourself from the sun [1].
- Pregnancy: this drug may harm an unborn baby; use effective contraception during treatment and tell your doctor straight away if you become pregnant. Do not breastfeed during treatment; men should also use effective contraception during treatment and for some time afterwards [1].
Frequently asked questions
Is hydroxyurea chemotherapy?
Yes, it is a mild oral chemotherapy drug; in blood disorders it is usually taken for years at a low dose with regular blood tests [1].
Related cancer types
References
3 referencesShow all references, 1 with a study cardClose the reference list
Numbers in the text, such as [1], refer to these sources. Sources with a “Study card” button are summarised in the site’s evidence library.
- 1
- 2
- 3
This page is based on reputable scientific sources and was last updated on 27 October 2026. The content of this website is for educational and informational purposes only and does not replace consultation, diagnosis or treatment by a specialist physician. Consult your treating physician about any treatment decision.
Printed from the website; the full and up-to-date version: https://drdabiri.com/en/drugs/hydroxyurea/