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Trade/other name(s): Hydrea, Droxia, hydroxycarbamide

Why would this drug be used?

Hydroxyurea is used to treat chronic myeloid leukemia and other cancers. It is also used to treat blood disorders including polycythemia vera and sickle cell anemia, as well as other conditions.

How does this drug work?

Hydroxyurea is a member of a general group of chemotherapy drugs called anti-metabolites. It keeps cells from making DNA by interfering with nucleic acids, which stops the growth of cancer cells.

Before taking this medicine

Tell your doctor…

  • If you are allergic to anything, including medicines, dyes, additives, or foods.
  • If you have any medical conditions such as kidney disease, liver disease (including hepatitis), heart disease, congestive heart failure, diabetes, gout, infections, or if you have had kidney stones. These conditions may require that your medicine dose, regimen, or timing be changed.
  • If you have ever taken interferon (a type of immune therapy). Taking hydroxyurea may put you at higher risk of a severe skin reaction.
  • If you are pregnant, trying to get pregnant, or if there is any chance of pregnancy. There's a chance this drug may cause birth defects if either the male or female is taking it at the time of conception or during pregnancy. Check with your doctor about what kinds of birth control can be used with this medicine.
  • If you are breast-feeding. The drug passes into breast milk and may harm the baby.
  • If you think you might want to have children in the future. Some drugs can cause sterility. Talk with your doctor about the possible risk with this drug and the options that may preserve your ability to have children.
  • About any other prescription or over-the-counter medicines you are taking, including vitamins and herbs. In fact, keeping a written list of each of these medicines (including the doses of each and when you take them) with you in case of emergency may help prevent complications if you get sick.

Interactions with other drugs

Any drugs or supplements that interfere with blood clotting can raise the risk of bleeding during treatment with hydroxyurea. These include:

  • vitamin E
  • non-steroidal anti-inflammatory drugs (NSAIDs) such as aspirin, ibuprofen (Advil, Motrin), naproxen (Aleve, Naprosyn), and many others
  • warfarin (Coumadin)
  • ticlopidine (Ticlid)
  • clopidogrel (Plavix)

Note that many cold, flu, fever, and headache remedies contain aspirin or ibuprofen. Ask your pharmacist if you aren't sure what's in the medicines you take.

Check with your doctor, nurse, or pharmacist about other medicines, vitamins, herbs, and supplements, and whether alcohol can cause problems with this medicine.

Interactions with foods

No serious interactions with food are known at this time. Check with your doctor, nurse, or pharmacist about whether foods may be a problem.

Tell all the doctors, dentists, nurses, and pharmacists you visit that you are taking this drug.

How is this drug taken or given?

Hydroxyurea is taken by mouth as a capsule. You should take the medicine with a full glass of water. Your dose depends on the reason you are taking it, how well your kidneys are working, and your blood counts. If hydroxyurea makes you feel sick to your stomach, take an anti-nausea pill an hour before taking it.

You should take this drug exactly as directed by your doctor. If you do not understand the instructions, ask your doctor or nurse to explain them to you.

Wash your hands after handling hydroxyurea. Do not let other people handle this medicine. If a capsule breaks, wipe up the powder with a damp paper towel and discard it in a closed container such as a plastic bag where children and pets cannot reach it. Talk to your doctor or pharmacist about how to dispose of unused or outdated capsules.

Store the medicine in a tightly closed container away from heat and moisture and out of the reach of children and pets.


This drug can kill large numbers of cancer cells within the first 24 hours of treatment, spilling the cells' contents into the blood. This can lead to electrolyte imbalances and tumor lysis syndrome, which can result in serious kidney damage and other problems. If your doctor thinks you may be at risk, he or she will give you medicines and/or fluids to help prevent it. Drink plenty of fluids while taking this drug.

Your doctor will likely test your blood throughout your treatment, looking for possible effects of the drug on blood counts (described below) or on other body organs. Based on the test results, you may be given medicines to help treat any effects. Your doctor may also need to reduce or delay your next dose of this drug, or even stop it altogether. Be sure to keep all your appointments for lab tests and doctor visits.

Hydroxyurea can lower your white blood cell count, especially a few days after the drug is given. This can increase your chance of getting an infection. Be sure to let your doctor or nurse know right away if you have any signs of infection, such as fever (100.5° or higher), chills, pain when passing urine, a new cough, or bringing up sputum.

Hydroxyurea may lower your platelet count, which can increase your risk of bleeding. Speak with your doctor before taking any drugs or supplements that might affect your body's ability to stop bleeding, such as aspirin or aspirin-containing medicines, warfarin (Coumadin), or vitamin E. Tell your doctor right away if you have unusual bruising, or bleeding such as nosebleeds, bleeding gums when you brush your teeth, or black, tarry stools.

Hydroxyurea may lower your red blood cell count. If this occurs, it may be a few weeks after starting treatment. A low red blood cell count (known as anemia) can cause shortness of breath, or make you to feel weak or tired all the time. Your doctor may give you medicines to help prevent or treat this condition, or you may need to get blood transfusions.

Do not get any immunizations (vaccines), either during or after treatment with this drug, without your doctor's OK. Hydroxyurea may affect your immune system. This could make vaccinations ineffective, or could even lead to serious infections if you get a live virus vaccine during or soon after treatment. Try to avoid contact with people who have recently received a live virus vaccine, such as the oral polio vaccine or smallpox vaccine.

Because of the way hydroxyurea acts on cells in the body, it may increase your long-term risk of getting a second type of cancer, such as leukemia. This is rare, but if it does occur it would likely be years after the drug is used. If you are getting this drug, your doctor feels this risk is outweighed by the risk of what might happen if you do not get this drug. You may want to discuss these risks with your doctor.

Avoid pregnancy during treatment and for some months afterward. This drug may harm a growing fetus. Talk with your doctor about this.

Possible side effects

You will probably not have most of the following side effects, but if you have any talk to your doctor or nurse. They can help you understand the side effects and cope with them.


  • low white blood cell count with increased risk of infection*

Less common

  • low red blood cell count (anemia) with symptoms such as tiredness, shortness of breath*
  • tiredness (fatigue)
  • skin rash or changes in nails
  • fetal abnormalities if pregnancy occurs while taking the drug


  • nausea
  • vomiting
  • sores in mouth or on lips
  • diarrhea
  • low platelet count with increased risk of bleeding*
  • headache
  • brain effects such as dizziness, confusion, hallucinations, and seizures
  • drowsiness
  • loss of appetite
  • high blood levels of uric acid, which can cause gout and damage kidneys
  • hair loss or thinning, including face and body hair (it grows back when drug is stopped)
  • abnormal blood tests which suggest that the drug is affecting the liver or the kidneys (Your doctor will discuss the importance of this finding, if any.)
  • second type of cancer*
  • death due to liver damage, infection, lung damage, or other causes

*See "Precautions" section for more detailed information.

There are some other side effects not listed above that can also occur in some patients. Tell your doctor or nurse if you develop these or any other problems.

FDA approval

Yes – first approved before 1984 (FDA cannot verify dates of drugs approved before 1984).

Disclaimer: This information does not cover all possible uses, actions, precautions, side effects, or interactions. It is not intended as medical advice, and should not be relied upon as a substitute for talking with your doctor, who is familiar with your medical needs.

Last Medical Review: 02/05/2010
Last Revised: 02/05/2010