How does it work?

Hydrea capsules contain the active ingredient hydroxycarbamide, which was previously known as hydroxyurea in the UK. (NB. Hydroxycarbamide is also available without a brand name, ie as the generic medicine.)

Hydroxycarbamide is a chemotherapy medicine. It is most commonly used to treat a cancer of the blood cells called chronic myeloid leukaemia (CML).

Cancers form when some cells within the body multiply uncontrollably and abnormally. Leukaemias are cancers that involve the blood cells multiplying abnormally.

Like normal healthy cells, cancer cells go through a continuous process of change. Each cell divides into two daughter cells. These cells grow, rest and then divide again, and thus increase in number. Chemotherapy medicines are powerful chemicals designed to interrupt this cycle and stop cells from growing and multiplying.

The exact way in which hydroxycarbamide works is unclear, but it appears to interfere with the synthesis of genetic material (DNA) inside cells. It therefore stops cells from growing and multiplying, which stops the growth of abnormal tissue. Hydroxycarbamide is used to stop the growth of abnormal cells in leukaemia and cervical cancer.

Hydroxycarbamide is also sometimes used to treat the myeloproliferative diseases polycythaemia vera (PV) and essential thrombocytosis (ET). In PV there is an excessive number of red blood cells in the blood, while in ET there is an excessive number of blood cells called platelets. Hydroxycarbamide reduces the excessive numbers of cells in these conditions.

Unfortunately, hydroxycarbamide can also affect normal, healthy cells, particularly those that multiply quickly, such as normal healthy blood cells. Hydroxycarbamide can decrease the production of white blood cells, leaving people susceptible to infection. Regular blood tests are therefore needed to monitor the levels of blood cells.

What is it used for?

• Cancer of the blood, characterised by an increased number of granulocytes in the blood (chronic myeloid leukaemia - CML)
• Cervical cancer, in conjunction with radiotherapy treatment
• Excessive numbers of red blood cells in the blood (polycythaemia vera)
• Excessive numbers of blood cells called platelets in the blood (essential thrombocythaemia)

Warning!

• If prefered, or if you are unable to swallow capsules, your dose can be taken by emptying the contents of the capsules into a glass of water and taking this immediately. However, if you do this, make sure you do not inhale the contents of the capsules, or allow them to come into contact with skin or mucous membranes.
• Hydroxycarbamide can decrease the number of blood cells in your blood. A low white blood cell count can increase your susceptibility to infections; a low red blood cell count causes anaemia and a low platelet count can cause problems with blood clotting. For this reason, you will need to have regular blood tests to monitor your blood cells during treatment with this medicine. Tell your doctor immediately if you experience any of the following symptoms during your treatment, as they may indicate problems with your blood cells: unexplained bruising or bleeding, purple spots, sore mouth or throat, mouth ulcers, high temperature (fever) or other signs of infection, or suddenly feeling tired, breathless, or generally unwell.
• While taking this medicine you will also need to have regular blood tests to monitor your kidney and liver function.
• This medicine can sometimes increase in the amount of uric acid in your blood, which can result in the development of gout or kidney problems. For this reason, while you are taking this medicine you should make sure you drink plenty of fluid. You will also need to have regular blood tests to monitor the amount of uric acid in your blood.
• Your ability to become pregnant or father a child may be affected by taking this medicine. It is important to discuss fertility with your doctor before starting treatment.

Use with caution in

• Elderly people
• Significantly decreased kidney function
• Gout
• People taking antiretrovirals for HIV infection

Not to be used in

• Severely decreased number of red blood cells in the blood (anaemia)
• Severely decreased number of white blood cells in the blood (leucopenia)
• Severely decreased number of platelets in the blood (thrombocytopenia)

This medicine should not be used if you are allergic to one or any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy.If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.

Pregnancy and Breastfeeding

Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.

• This medicine should not be used during pregnancy, unless considered essential by your doctor, as it may be harmful to the unborn baby. Women who could get pregnant should use effective contraception to prevent pregnancy, and men should use effective contraception to prevent fathering a child, both during treatment, and for at least a few months after treatment is finished. Seek medical advice from your doctor.
• This medicine passes into breast milk and may be harmful to a nursing infant. For this reason, mothers who who need to take this medicine should discontinue breastfeeding. Seek medical advice from your doctor.

Side effects

Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Because a side effect is stated here, it does not mean that all people using this medicine will experience that or any side effect.

• Decrease in the number of white blood cells in the blood (leucopenia)
• Decrease in the number of platelets in the blood (thrombocytopenia)
• Decrease in the number of red blood cells in the blood (anaemia)
• Loss of appetite
• Disturbances of the gut such as diarrhoea, constipation, nausea, vomiting or abdominal pain
• Headache
• Drowsiness
• Dizziness
• Inflammation of the lining of the mouth (stomatitis)
• Fever
• A general feeling of being unwell (malaise) or feeling weak
• Hair loss (alopecia)
• Skin rashes or ulcers
• Red and sore skin in areas treated with radiotherapy
• Disorientation
• Lung disorders (tell your doctor if you feel short of breath during treatment)
• False perceptions of things that are not really there (hallucinations)
• Seizures (convulsions)
• Kidney disorders
• Redness, scaling or increased pigmentation of skin, or thinning of skin or nails in some people taking the medicine on a daily basis for long periods of time.

The side effects listed above may not include all of the side effects reported by the drug's manufacturer.For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.

How can this medicine affect other medicines?

It is important to tell your doctor or pharmacist what medicines you are already taking, including those bought without a prescription and herbal medicines, before you start treatment with this medicine. Similarly, check with your doctor or pharmacist before taking any new medicines during treatment this one, to ensure that the combination is safe.

There is a increased risk of side effects on normal healthy blood cells, such as a decrease in white blood cell count, if you are also receiving, or have recently received, other treatments that can affect the blood cells, for example radiotherapy treatment, or treatment with other chemotherapy medicines.

This medicine can decrease the body's immune response. This means that vaccines may be less effective if given during treatment, and live vaccines may cause serious infections. Live vaccines include: measles, mumps, rubella, MMR, oral polio, oral typhoid and yellow fever. If live vaccines are needed they should be postponed until at least six months after finishing chemotherapy.

If hydroxycarbamide is taken in combination with antiretrovirals to treat HIV infection, in particular stavudine and didanosine, there may be an increased risk side effects on the nerves, or liver damage or inflammation of the pancreas (pancreatitis) that may be life-threatening. Hydroxycarbamide is not licensed for use in combination with antiretroviral medicines for HIV infection and it may cause these treatments to fail.

Other medicines containing the same active ingredient

Hydroxycarbamide capsules are available without a brand name, ie as the generic medicine.