Hydroxycarbamide (Hydrea, hydroxyurea)

Hydroxycarbamide is used to treat chronic myeloid leukaemia (CML). It can also be used to treat acute myeloid leukaemia, head and neck cancers (before radiotherapy treatment) and ovarian cancer. Hydroxycarbamide is one of a group of chemotherapy drugs known as the anti metabolites. These drugs stop cells making and repairing DNA. Cancer cells need to make and repair DNA in order to grow and multiply.

Hydroxycarbamide comes as 500mg capsules. Your doctor may ask you to take these in one dose or in several doses during the day. You swallow them whole with plenty of water. If you have trouble swallowing, you can empty the capsules into a glass of water and drink all of it straight away. Never leave any behind in the glass. You need to have the whole chemotherapy dose and if you leave some, someone else could drink it by mistake, which could harm them.

It is very important that you take tablets according to the instructions your doctor or pharmacist gave you. Whether you have a full or empty stomach, for example, can affect how much of a drug gets into your bloodstream. You should take the right dose, not more or less. And never stop taking a cancer drug without talking to your specialist first.

You usually have hydroxycarbamide as a course of several cycles of treatment. Sometimes there may be a break between cycles. The exact treatment plan depends on which type of cancer you have. To find out more about the way chemotherapy treatment is planned click on planning chemotherapy.

The side effects associated with hydroxycarbamide are listed below. You can use the links (underlined) to find out more about each side effect. Where there is no link please see our cancer drugs side effects section, or click on search at the top of the page.

More than 10 in every 100 people have one or more of the side effects listed below.

Temporary drop in the number of blood cells made by the bone marrow, causing

• Increased risk of getting an infection from a drop in white blood cells – it is harder to fight infections and you can become very ill. You may have headaches, aching muscles, a cough, sore throat, pain passing urine or feel cold and shivery
• Tiredness and breathlessness due to a drop in red blood cells (anaemia) – you may need a blood transfusion
• Bruising more easily due to a drop in platelets – you may have nosebleeds, bleeding gums after brushing your teeth, or lots of tiny red spots or bruises on your arms or legs (known as petechia)

Some of these side effects can be life threatening, particularly infections. You should contact your doctor if you have any of these side effects. Your doctor will check your blood counts regularly to see how well your bone marrow is working.

Other common side effects include

• Fatigue during and after treatment – most people find their energy levels are back to normal from 6 months to a year after treatment ends
• A harmful effect on a baby that is developing in your womb – it is not advisable to become pregnant or father a child if you are having this drug so talk about contraception with your doctor before having the treatment if it is possible for you or your partner to become pregnant
• Women may stop having periods (amenorrhoea) but this may only be temporary
• Loss of fertility – you may not be able to get pregnant or father a child after treatment with this drug so talk to your doctor about fertility before starting treatment if having a baby is important to you

Fewer than 1 in 100 people have these.

• Feeling or being sick is usually mild – ask your doctor if you can take your tablets in several doses as this may reduce the sickness
• Sore mouth
• Loss of appetite
• Constipation – your doctor or nurse may give you laxatives to help
• Diarrhoea – you should drink plenty of fluids. If it becomes severe or persistent you could become dehydrated so you should tell your doctor or nurse
• Confusion or drowsiness
• Headache
• Rash or facial redness
• Painful leg ulcers that go away slowly after the treatment ends
• Fever and chills
• Hair loss is very unlikely but can happen for some people
• A small risk  that you may get a leukaemia or a skin cancer if you take hydroxycarbamide long term for a myeloproliferative disorder – don’t sit out in the sun and remember to cover up or use sun block on exposed skin

The side effects above may be mild or more severe. A side effect may get better or worse through your course of treatment, or more side effects may develop as the course goes on. This depends on

• How many times you've had the drug before
• Your general health
• The amount of the drug you have (the dose)
• Other drugs you are having

Talk to your doctor, pharmacist or nurse about all your side effects so that they can help you manage them. Your chemotherapy nurse, clinic or ward nurse will give you a contact number. You can ring if you have any questions or problems. They can give you advice or reassure you. If in doubt, call them.

Tell your doctor about any other medicines you are taking, including vitamins, herbal supplements and other over the counter remedies – some drugs can react together.

You should not have immunisations with live vaccines while you are having this treatment or for at least 6 months afterwards. In the UK, these include rubella, mumps, measles (usually given together as MMR), BCG and yellow fever. You can have other vaccines, but they may not give you as much protection as usual until your immune system has fully recovered.

It is safe for you to be in contact with other people who've had live vaccines as injections. There can be problems with oral vaccines, but not many people in the UK have oral vaccines now. So there is usually no problem in being with any baby or child who has recently had any vaccination in the UK. You might need to make sure that you aren't in contact with anyone who has had oral polio, cholera or typhoid vaccination recently, particularly if you live abroad.