What is it used for?

• Chronic myeloid leukaemia (CML).
• Cervical cancer, in conjunction with radiotherapy treatment.
• A condition called polycythaemia vera, in which there are excessive numbers of red blood cells in the blood.
• A condition called essential thrombocythaemia, in which there are excessive numbers of blood cells called platelets in the blood.

How does it work?

• Hydrea capsules contain the active ingredient hydroxycarbamide. Hydroxycarbamide capsules are 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), but is also used to treat cervical cancer and some other blood disorders.
• 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 during treatment.

How do I take it?

• The dose of hydroxycarbamide to take and how often to take it will vary from person to person depending on the condition that is being treated. The medicine is usually taken either once daily or once every three days. It is important to follow the instructions given by your doctor and printed on the dispensing label. This medicine must only be taken under specialist medical supervision.
• Hydroxycarbamide can be taken either with or without food. The capsules should be swallowed whole without sucking or chewing. However, if you have problems swallowing the capsules, the contents of the capsules can be emptied into a glass of water. If you do this, make sure you do not inhale the contents of the capsules, or allow the powder to come into contact with your skin, eyes, or inside of your nose. The solution must be drunk straight away.
• If you vomit after taking a dose or forget to take a dose you should ask your doctor for advice. Don't take a double dose to make up for a missed dose.
• It is important to make sure that you drink plenty of fluids while taking this medicine.

Not to be used in

• People with a very low number of red blood cells in the blood (anaemia).
• People with a very low number of white blood cells in the blood (leucopenia).
• People with a very low number of platelets in the blood (thrombocytopenia).

This medicine should not be used if you are allergic to 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 a developing baby.
• Women who could get pregnant must 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 not breastfeed. Ask your doctor for further advice.

Side effects

Decrease in the number of healthy white blood cells, red blood cells or platelets in the blood (neutropenia, anaemia and thrombocytopenia).

• Feeling or being sick. You will be given medicines to help with this.
• Disturbances of the gut such as diarrhoea, constipation or abdominal pain.
• Loss of appetite.
• Inflammation of the lining of the mouth, causing a sore mouth or mouth ulcers (stomatitis).
• Fever or chills.
• A general feeling of being unwell (malaise) or feeling weak.
• Skin rashes or ulcers.
• Increased level of uric acid in the blood, which may cause kidney problems or gout (see warning section above).
• Headache.
• Drowsiness.
• Dizziness.
• Disorientation.
• Seizures (convulsions).
• False perceptions of things that are not really there (hallucinations).
• Hair loss (alopecia).
• Red and sore skin in areas treated with radiotherapy.
• 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.
• Lung disorders (tell your doctor if you feel short of breath during treatment).

The side effects listed above may not include all of the side effects reported by the medicine'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 make sure 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 having, or have recently had, other treatments that can affect the blood cells, for example radiotherapy, other chemotherapy medicines, or the antipsychotic clozapine.

Vaccines may be less effective in people receiving chemotherapy. This is because chemotherapy medicines reduce the activity of the immune system and can prevent the body forming adequate antibodies. Live vaccines should be postponed until at least six months after finishing chemotherapy because they may cause infection. Live vaccines include the following: oral polio; rubella; measles, mumps and rubella (MMR); BCG; chickenpox; yellow fever and oral typhoid vaccines.

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.

References:

https://www.drugs.com/cdi/hydrea.html

https://www.rxlist.com/hydrea-drug.htm

http://chemocare.com/chemotherapy/drug-info/hydroxyurea.aspx

https://www.medicinenet.com/hydroxyurea-oral/article.htm

https://en.wikipedia.org/wiki/Hydroxycarbamide

https://medlineplus.gov/druginfo/meds/a682004.html