Ondrea
✅ Reduces sickle cell crises
✅ Prevents painful episodes
✅ Increases hemoglobin levels
✅ Lowers risk of complications
✅ Improves quality of life
Ondrea contains Hydroxyurea.
✓ Medically reviewed by Morgan Ellis — Pharmacy Researcher · 8 years experience · Last reviewed: May 2026
⚡ Quick Answer — What is Ondrea?
Ondrea is an oral capsule from Cipla containing hydroxyurea (hydroxycarbamide) 500 mg — a ribonucleotide reductase inhibitor used for chronic myeloid leukaemia, polycythaemia vera, essential thrombocythaemia, sickle cell disease, and several solid tumours (head & neck, melanoma). Standard adult dosing varies by indication: typically 15–30 mg/kg/day in haematology; 20–35 mg/kg/day in sickle cell. Mandatory monitoring: FBC every 2 weeks initially, then monthly — titrate to ANC > 2,000/µL and platelets > 100,000/µL. Pregnancy contraindication; reliable contraception in both sexes throughout treatment. Long-term concern: leg ulcers (chronic, painful), squamous cell skin cancers, possible secondary leukaemia (controversial, mainly in long-term polycythaemia vera).
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What Is Ondrea?
Ondrea is an oral capsule from Cipla containing hydroxyurea 500 mg (also called hydroxycarbamide). Hydroxyurea inhibits ribonucleotide reductase, blocking DNA synthesis. It is one of the most widely-used and longest-established cytoreductive agents, with a 60-year clinical safety record across haematological malignancies, sickle cell disease and several solid tumours.
Uses and Indications
- Chronic myeloid leukaemia — cytoreduction at diagnosis or as alternative when TKIs (imatinib etc) cannot be used
- Polycythaemia vera — first-line cytoreduction in high-risk disease
- Essential thrombocythaemia — first-line cytoreduction in high-risk disease
- Myelofibrosis (early phase) — symptom and counts control
- Sickle cell disease — reduces frequency of vaso-occlusive crises and acute chest syndrome; raises HbF
- Acute leukaemia — emergency leukocytosis reduction (rapid cytoreduction before definitive therapy)
- Head and neck squamous cell carcinoma — with concurrent radiotherapy (older regimens)
- Melanoma, ovarian cancer (limited modern use)
Dosage and How to Take
Dose varies by indication. Examples for adults:
- CML, ET, PV cytoreduction: start 15 mg/kg/day; titrate to 15–30 mg/kg/day based on counts
- Sickle cell disease: start 15 mg/kg/day; increase by 5 mg/kg/day every 8 weeks to maximum 35 mg/kg/day or maximal tolerated dose
- Acute leukaemia emergency cytoreduction: 50–100 mg/kg/day for 1–2 days (specialist)
- Take once or twice daily as prescribed, with or without food.
- Swallow capsules whole. Do NOT open capsules — the powder is cytotoxic and harmful on contact. If a capsule cannot be swallowed, the contents can be dispersed in water with caregiver wearing gloves and avoiding skin/eye contact.
- Mandatory monitoring: FBC every 2 weeks initially (or weekly during titration in sickle cell), then monthly. U&E + LFTs every 1–3 months. Reticulocyte count, HbF (sickle cell). MCV rises on hydroxyurea (a useful marker of compliance).
- Dose adjustments based on counts: hold for ANC < 2,000/µL, platelets < 80,000/µL, or Hb < 4.5 g/dL. Resume at lower dose once recovered.
- Folic acid 5 mg daily often co-prescribed (especially in haemoglobinopathy).
- Drink plenty of fluids to reduce risk of hyperuricaemia and tumour lysis syndrome.
Side Effects
Common: myelosuppression (the desired effect at therapeutic dose), nausea, anorexia, mucositis, mild diarrhoea, skin hyperpigmentation, nail pigmentation, hair thinning.
Important:
- Leg ulcers — chronic, painful, slow-healing; affects ~5% of long-term users; may require dose reduction or discontinuation
- Squamous cell skin cancers — long-term users, especially fair-skinned; annual dermatology review and rigorous SPF use
- Macrocytosis (raised MCV) — expected, marker of compliance, not a problem
- Pulmonary fibrosis (rare)
- Hyperuricaemia, gout
- Possible secondary leukaemia in long-term polycythaemia vera (controversial)
Warnings
- Pregnancy: teratogenic. Strong contraception throughout treatment AND for 6 months after the last dose, in BOTH male and female patients.
- Breastfeeding: excreted in breast milk — avoid.
- Renal impairment: reduce dose for eGFR < 60 mL/min.
- Severe hepatic impairment: caution.
- Skin cancer screening: annual dermatology review for long-term users; rigorous daily SPF.
- Vaccinations: live vaccines contraindicated; inactivated vaccines safe and recommended.
- HIV co-infection: hydroxyurea + didanosine combination has caused fatal pancreatitis — avoid.
Drug Interactions
| Combine with | Effect | What to do |
|---|---|---|
| Didanosine (HIV antiretroviral) | Fatal pancreatitis reported | Absolutely avoid combination. |
| Other myelosuppressive drugs (chemotherapy, immunosuppressants) | Additive marrow suppression | Specialist supervision; close FBC monitoring. |
| Live vaccines | Disseminated infection risk | Contraindicated. |
| Allopurinol or febuxostat | Useful for hyperuricaemia / gout from cell turnover | Often co-prescribed. |
Storage
- Room temperature, 15–30°C, original blister.
- Keep out of reach of children, women of childbearing potential, pets.
- Caregivers handling broken capsules should wear gloves — powder is cytotoxic.
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Frequently Asked Questions
How does Ondrea help in sickle cell disease?
Hydroxyurea is the most important disease-modifying drug for sickle cell. It raises fetal haemoglobin (HbF) levels, which prevents red cells from sickling. Effects: ~50% reduction in vaso-occlusive crises, fewer hospitalisations, less acute chest syndrome, lower blood transfusion requirement, improved survival. Most patients see clinical benefit at 8–12 weeks of dose titration; full benefit at 6–12 months. Underused worldwide despite a strong evidence base — talk to your haematologist if you have sickle cell and have not been offered hydroxyurea.
What blood tests do I need on Ondrea?
Mandatory: FBC every 2 weeks initially (weekly during sickle cell titration), then monthly once stable. U&E + LFTs every 1–3 months. Sickle cell patients also: HbF measurement, reticulocyte count. Hold or reduce dose for ANC < 2,000/µL, platelets < 80,000/µL, or Hb < 4.5 g/dL.
Why is Ondrea associated with leg ulcers?
Chronic, painful leg ulcers affect ~5% of long-term hydroxyurea users, mostly around the malleolus (ankle). Mechanism is unclear (probably microvascular). They are slow to heal and may require dose reduction or hydroxyurea discontinuation. Tell your doctor immediately if you develop a leg ulcer on hydroxyurea — do not delay.
Will Ondrea cause cancer?
Long-term hydroxyurea use slightly increases the risk of squamous cell skin cancers, especially in fair-skinned patients. Annual full-skin dermatology review, daily broad-spectrum SPF, sun avoidance. The historic concern about secondary leukaemia in polycythaemia vera on long-term hydroxyurea is debated — large modern data suggest the risk is low and that PV itself carries an inherent leukaemic transformation risk.
Can I get pregnant on Ondrea?
Hydroxyurea is teratogenic. Reliable contraception is mandatory throughout treatment AND for at least 6 months after the last dose, in both male and female patients. Discuss family planning with your haematologist before starting. In sickle cell, hydroxyurea is sometimes held during planned pregnancy with close monitoring.
Why does my MCV go up on Ondrea?
Macrocytosis (raised MCV) is an expected and useful effect — it indicates you are taking the drug consistently. Doctors use MCV as a compliance marker in sickle cell. The rise is benign and not associated with any clinical problem.
Can I open a capsule if I cannot swallow it?
Best avoided — the powder is cytotoxic and harmful on skin, eye and respiratory contact. If essential, the caregiver must wear gloves, work in a ventilated area, and disperse the contents in a small amount of water for the patient to drink immediately. Wash hands and surfaces afterwards. Specialist pharmacist can prepare a liquid suspension as an alternative.
Can I take Ondrea with HIV antiretrovirals?
Most ART is compatible. The dangerous combination is hydroxyurea + didanosine, which has caused fatal pancreatitis. Tell every prescriber about both medications and ensure no didanosine is in your regimen.
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| Strength | 500 mg |
|---|---|
| Quantity | 90 Tablet/s, 180 Tablet/s, 270 Tablet/s, 540 Tablet/s |
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