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Cytoreductive agent / Sickle cell disease / CML

Hydroxycarbamide (Hydroxyurea)

Brand names: Siklos, Xromi, Hydrea

Hydroxycarbamide (hydroxyurea) is an oral antimetabolite cytoreductive agent used in myeloproliferative neoplasms such as polycythaemia vera and essential thrombocythaemia, in chronic myeloid leukaemia, and to reduce vaso-occlusive crises in sickle cell disease.

Dosing — being independently re-sourced

ClinCalc Pro is rebuilding its dose data from primary open sources — the manufacturer SmPC (eMC), the WHO Model Formulary and other official references — under clinician review. This drug's structured dose is not yet published here. Confirm all doses against the product SmPC and your local formulary before prescribing.

Clinical monograph

How it works

It inhibits ribonucleotide reductase, depleting deoxynucleotides and arresting DNA synthesis; in sickle cell disease it also raises fetal haemoglobin, reducing red-cell sickling.

Prescribing in practice

  • Myelosuppression is dose-limiting and necessitates regular full blood count monitoring with dose adjustment for cytopenias.
  • It is teratogenic, so effective contraception is required during and for a period after treatment in both men and women of reproductive potential.
  • Cutaneous reactions including leg ulcers and rarely secondary malignancy can occur with long-term use, warranting periodic skin review.

Monitoring

Monitor full blood count regularly, together with renal and hepatic function, adjusting the dose to maintain counts within target while avoiding excessive myelosuppression.

Counselling the patient

  • Attend for your regular blood tests so the dose can be kept safe.
  • Report any unusual bruising, bleeding, fever, mouth ulcers or new skin ulcers promptly.
  • Use reliable contraception and tell your team if you plan a pregnancy.

Evidence & guidelines

Hydroxycarbamide is established for sickle cell disease following the landmark MSH trial and is recommended by NICE and national guidelines for myeloproliferative neoplasms.

Reference: NICE NG143 Sickle Cell Disease; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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