This drug lowers the number of blood cells produced by your bone marrow. Hydroxycarbamide (formerly known as hydroxyurea) goes under the brand name Hydrea® and is a very common treatment for all myeloproliferative neoplasms (MPNs). Hydroxycarbamide comes as a capsule and is taken orally. Most people who take the drug in low doses find that they don’t have too many side effects.

Hydroxycarbamide reduces the number of blood cells produced by your bone marrow. Hydroxycarbamide is considered a chemotherapy medication because it slows the growth of blood cells, however most MPN patients actually take quite low doses of this drug. Patients should be aware that the prescribing regulations for hydroxycarbamide are included with those of other chemotherapy drugs and for this reason patients may be asked to sign a consent to treatment form before starting the drug for the first time.

Your haematologist may recommend that you take hydroxycarbamide in combination with low dose aspirin. If you have polycythaemia vera you may need phlebotomy as well.

How it works

Hydroxycarbamide reduces production of all blood cells by slowing cell division in the bone marrow.

Why take this drug

Most people tolerate hydroxycarbamide very well because it comes as a capsule and is easy to take. It is also very effective at bringing blood counts down to normal levels, reducing the risk of clots or bleeding in most people with MPNs. There is also evidence to suggest that hydroxycarbamide reduces the long-term risk of bone marrow scaring or myelofibrosis.

If you have essential thrombocythaemia (ET), hydroxycarbamide can reduce your platelet counts.

If you have polycythaemia vera (PV), this medication can lower both your red cell and platelet counts.

If you have myelofibrosis (MF), your doctor may recommend hydroxycarbamide because it can help reduce the size of your spleen and reduce the fatigue and breathlessness you may be feeling.

People taking hydroxycarbamide may feel fewer of the symptoms they experience with an MPN.  The drug often reduces headaches, visual problems, fatigue, tingling in fingers and toes and itching.

Common side effects

Low cell counts Hydroxycarbamide can cause side effects because the drug reduces blood cell counts across the board. If your red blood cell count drops too low you may develop anaemia and find that you become breathless and tire easily. If your platelet count drops too low you may experience nose bleeds, bleeding gums when you brush your teeth, a rash of tiny red spots or increased bruising. If your white cell count drops too low your risk of developing infections may increase. Your haematologist will monitor your blood counts to ensure your blood counts don’t drop too low. It is important you do not miss any of your clinic appointments.  If you are experiencing any unusual symptoms, you should contact your doctor right away.

Increased fatigue Hydroxycarbamide can increase fatigue. However, it is sometimes difficult to know whether the drug itself is causing the fatigue as feeling tired is also a symptom of MPNs.

Changes to the skin Hydroxycarbamide can cause changes to the skin, such as skin darkening. It may increase the risk of skin cancer, so please take extra care in the sunshine. It can cause mouth and leg ulcers especially with long-term use.

Abdominal symptoms You might also experience diarrhoea or constipation while taking this drug.

Long-term risks There may be risks to taking hydroxycarbamide over a period of many years. There is some evidence that hydroxycarbamide may increase the risk of skin cancer, and there is a possibility that it might in rare cases increase the risk of leukaemia. If you are taking hydroxycarbamide you need to protect yourself from the sun with adequate clothing, sunscreen and a hat – and where possible stay out of the sun. If you have questions about long-term risks, please talk with your doctor or haematologist.

Hydroxycarbamide FAQs

Can I eat and drink normally? Yes. We recommend that you eat a normal, healthy diet and drink plenty of water.

Can I drink alcohol? While it is safe to drink alcohol in moderation while taking hydroxycarbamide, we recommend you do not exceed the recommended weekly limits of 14 units of alcohol per week for men and women.  Alcohol can cause dehydration, and it is important to avoid becoming dehydrated if you have an MPN.  Please ask your nurse or doctor if you require more information regarding alcohol consumption.

What if I want to have a child? We recommend against taking hydroxycarbamide if you are trying to become pregnant or to father a child.  Please see our pregnancy section for more information on pregnancy in MPNs.

Who will prescribe hydroxycarbamide for me? Your doctor, specially-trained nurse, hospital pharmacist or sometimes your GP will prescribe your medication.

Can I drive? Hydroxycarbamide is not known to cause drowsiness that could affect your driving, however if you are feeling drowsy or fatigued for any reason do not drive.

Do I need to take any special precautions? Your skin may be more sensitive to the sun whilst you are taking hydroxycarbamide so it would be wise to avoid exposure to the sun, using sunscreen and wearing protective clothing and a hat. If you are undergoing radiotherapy (radiation treatment) you need to stop taking hydroxycarbamide. Please check with your medical team for detailed information.

Taking other medications Whenever you take hydroxycarbamide (or in fact any medication), it is important to inform your medical advisors about all other medications you are taking: this includes medicines prescribed for you as well as any vitamins, herbal supplements or remedies bought in chemists. Always provide the names of these medications and remedies to the hospital doctors, GPs, nurses and pharmacists who are treating you, prescribing additional medications or giving you advice. It can be very helpful to carry a list of the names and dosages of all your medicines to show to your doctor or nurse at appointments.

Some medicines may interact with hydroxycarbamide. These include:

  • Clozapine (Clozaril, Denzapine, Zaponex)
  • Didanosine (Videx)
  • Stavudine (Zerit)
  • Chemotherapy drugs
  • Medicines that are damaging to the bone marrow
  • Medicines used to treat HIV

Can I have vaccinations such as the flu jab? Yes, you can have most vaccinations including the flu vaccine whilst taking hydroxycarbamide. Some vaccinations are live vaccines and these should not be taken with hydroxycarbamide. It is important you tell the person giving you the vaccine that you are taking hydroxycarbamide so they can verify it is safe for you to be vaccinated.

More information

If you’d like more information you can download our leaflets about MPN medications.