Overview

Sickle cell disease is a condition that affects the body's red blood cells. It is an inherited condition, and is life long. It's also known as sickle cell disorder. 

Hydroxycarbamide, also known as hydroxyurea, is a medicine used to treat sickle cell disease.

It causes changes in the blood which help to reduce the frequency of sickle cell crises, and the need for blood transfusions. 

Who can take hydroxycarbamide

Hydroxycarbamide may be recommended if:  

• you have moderately severe or severe sickle cell 
• you’ve been to the emergency department (A&E) and have had to be admitted 3 or more times in the last year because of sickle cell crises
• you've had a chest crisis (acute chest syndrome) and needed a blood transfusion, or admission to the high dependency unit (HDU) 
• you've had a stroke, and can no longer have exchange blood transfusions 
• you have any other sickle cell complications 

Taking an unlicensed medicine

The brand of hydroxycarbamide that we prescribe is not licenced for the treatment of sickle cell disease. Your consultant will discuss this with you in more detail.

You can read our information about unlicensed medicines.

If you have any questions or concerns, please speak to your sickle cell team. 

How it works

Hydroxycarbamide increases the amount of fetal haemoglobin (HbF) in your red blood cells. HbF helps red blood cells stay round and flexible, allowing them to move more easily through your blood vessels. This makes them less likely to clump together or cause blockages that lead to sickle cell crises.

Benefits of hydroxycarbamide 

Hydroxycarbamide is not a cure for sickle cell disease. However, it can help by reducing: 

• painful crises and how often you have them 
• how often you are admitted to hospital because of sickle cell complications 
• chest crises (acute chest syndrome)
• how often you need blood transfusions
• anaemia (low haemoglobin) as it makes the red blood cells last longer in the body
• the amount of white blood cells, especially neutrophils. Neutrophils are important in fighting infection in the body, but high amounts in people with sickle cell can cause inflammation, trigger crises, and other complications
• the amount of blood cells involved in clotting (platelets)

Hydroxycarbamide does not help with: 

• leg ulcers
• bone damage (avascular necrosis)
• infections

Hydroxycarbamide may help you live longer, and improve your quality of life.  

It usually takes at least 3 months before you can tell if the hydroxycarbamide is working.

Side effects

Some of the side effects of hydroxycarbamide are listed below.

Please see the manufacturer’s information leaflet that comes with the medicine for more information.

You should let your doctor or nurse know if you have any side effects. Any side effects will be closely monitored by your haematologist or nurse specialist. 

Monitoring your health

You'll need regular blood tests and monitoring while you take this medicine. This includes monitoring your:

• blood count
• fetal haemoglobin (HbF) level
• liver and kidney function

After you start taking hydroxycarbamide, or if we change your dose (amount), we’ll invite you back for a blood test 2 weeks later to check how you're doing.

When your blood counts are stable, you'll be seen every 8 to 12 weeks. Your dose may be reduced if your blood count drops.

Please make sure that you attend all of your blood tests, as this will help us to identify any changes to your blood counts early on. We will not be able to prescribe hydroxycarbamide if you do not come for regular blood tests as we need to be able to monitor you.

If you do not have regular blood monitoring, changes in your blood count will not be recognised early and this may be dangerous.

We may lower your dose, or tell you to stop taking the medicine temporarily if you have severe side effects or if your blood counts drop. 

Your haematologist will usually recommend that you restart taking hydroxycarbamide when your blood count has been checked and is normal.

Fertility, pregnancy and breastfeeding

Advice for men 

Fertility 

Hydroxycarbamide can affect the production of sperm and reduce the sperm count. We recommend that you have a sperm sample checked and stored before you start taking the medicine. Your haematologist can arrange this.

Pregnancy and contraception 

We recommend that men use an effective method of contraception while taking hydroxycarbamide, as the medicine can potentially be harmful to a developing baby.

If you and your partner are planning to become pregnant, you need to stop taking hydroxycarbamide 3 to 6 months before you try to conceive.

Advice for women 

Pregnancy and contraception 

Taking hydroxycarbamide during pregnancy is not recommended. 

If you are planning to become pregnant, you should stop taking hydroxycarbamide at least 6 months before trying to get pregnant. You should use an effective method of contraception during this time.

If you become pregnant while you are taking hydroxycarbamide, stop taking it immediately and contact your sickle cell team as soon as possible. You may need extra monitoring throughout your pregnancy.

Even if you are not taking hydroxycarbamide, it's important that you let your sickle cell team know that you are planning a pregnancy. They will help you to be in the best possible health before you become pregnant.

Read our information about sickle cell disease and pregnancy. 

Breastfeeding

You should not breastfeed if you are taking hydroxycarbamide, as small amounts of the medicine might be in your breast milk. If you were planning to breastfeed, speak to your sickle cell team or midwife for advice.