Hydroxyurea

Hydroxyurea is a prescription medication used to reduce the frequency of episodes of severe pain from sickle cell anemia and to reduce the need for blood transfusions in adults with sickle cell anemia. Hydroxyurea belongs to a group of drugs called antineoplastic agents. How it works is not known. It may prevent red blood cells from bending into the wrong shape, and by reducing the number of white blood cells and/or increasing red blood cells that carry fetal hemoglobin (HbF).

This medication comes in capsule form and is usually taken once a day, with or without food. Drink 8 to 10 glasses of water each day while you are taking hydroxyurea.

Some of the common side effects of hydroxyurea include hair loss, fever, and stomach problems. 

Hydroxyurea is a prescription medicine that is used to reduce the frequency of painful crises (episodes of severe pain) and reduce the need for blood transfusions in adults with sickle cell anemia. 

This medication may be prescribed for other uses. Ask your doctor or pharmacist for more information.

Hydroxyurea may be found in some form under the following brand names:

• Droxia

• Hydrea

• Mylocel

As with other medicines, hydroxyurea may cause unwanted effects, although it is not always possible to tell whether such effects are caused by hydroxyurea, another medication you may be taking, or your sickle cell anemia. Any side effects or unusual symptoms that you experience should be reported to your doctor, particularly if they persist or are troublesome.

The most serious side effects of hydroxyurea involve the blood and may include severely low white blood cell counts (leukopenia, neutropenia), which can decrease your resistance to infections, severely low red blood cell counts (anemia), or severely low platelet counts (thrombocytopenia), which can cause bleeding. Almost all patients who received hydroxyurea in clinical studies needed to have their medication stopped for a time to allow their low blood counts to return to acceptable levels.

The side effects reported most often by adults with sickle cell anemia participating in studies of hydroxyurea included hair loss, skin rash, fever, stomach and/or bowel disturbances, weight gain, bleeding, virus infection, and discolored nails (melanonychia), but these were equally common in people getting a placebo (sugar pill).

Skin cancer and leukemia, which can be fatal, have been reported in patients receiving long-term hydroxyurea for conditions other than sickle cell anemia. In laboratory tests, hydroxyurea causes changes in chromosomes and DNA (genetic material) that strongly suggest it can cause cancer in people, especially if it is taken for a long time.

Skin ulcers have been seen in patients taking hydroxyurea therapy. Contact your doctor if skin ulcers develop while you are taking hydroxyurea.

Your doctor should measure your blood counts every two weeks while you are taking hydroxyurea. Your hydroxyurea dose will require adjustment based on these regular blood counts. Serious problems can occur if the hydroxyurea dose is not adjusted on time.

Some other medications can increase your risk of experiencing serious side effects from hydroxyurea. While you are taking hydroxyurea capsules, you should inform your doctor of all prescription and over-the-counter medicines that you are taking.

Hydroxyurea capsules are used to treat sickle cell anemia in adults. Hydroxyurea reduces the frequency of painful crises and reduces the need for blood transfusions.

• It is VERY IMPORTANT that you have regular blood counts so that your doctor can decrease or increase the hydroxyurea dose as needed to avoid serious complications.
• The most serious side effects of hydroxyurea involve the blood and may include severely low white blood cell counts (leukopenia, neutropenia), which can decrease your resistance to infections, severely low red blood cell counts (anemia), or severely low platelet counts (thrombocytopenia), which can cause bleeding. Almost all patients who received hydroxyurea in clinical studies needed to have their medication stopped for a time to allow their low blood counts to return to acceptable levels.
• If you get pregnant, hydroxyurea may harm or cause death to your unborn child. You should not become pregnant while taking hydroxyurea. Make sure you use a contraceptive method. Tell your doctor if you become pregnant or plan to become pregnant while taking hydroxyurea.
• Hydroxyurea may decrease the ability of men to father children and women to have children.
• Laboratory tests and reports in humans suggest hydroxyurea may increase your risk of developing cancer, especially if it is taken for a long time. However, it is still uncertain whether hydroxyurea causes cancer.

Do not take hydroxyurea capsules if you are allergic to any of the ingredients.  Tell your doctor if you think you have ever had an allergic reaction.

Medications can interact with certain foods. In some cases, this may be harmful and your doctor may advise you to avoid certain foods. In the case of hydroxyurea, there are no specific foods that you must exclude from your diet when receiving this medication.

Before taking hydroxyurea, tell your doctor about all of your medical conditions. Especially tell your doctor if you:

• are allergic to hydroxyurea or to any of its ingredients
• have HIV

• have liver problems
• have kidney problems
• are pregnant or breastfeeding

Tell your doctor about all the medicines you take including prescription and non-prescription medicines, vitamins, and herbal supplements.

If you get pregnant, hydroxyurea may harm or cause death to your unborn child. You should not become pregnant while taking hydroxyurea. Make sure you use a contraceptive method. Tell your doctor if you become pregnant or plan to become pregnant while taking hydroxyurea.

In nursing mothers, hydroxyurea is present in breast milk. Because of the potential for side effects in the newborn, you should discontinue nursing your baby while taking hydroxyurea.

Always follow your doctor’s instructions carefully when taking hydroxyurea capsules or any prescription medication.

The usual dose of hydroxyurea may range from as few as one to several capsules per day. Hydroxyurea is usually taken once a day. You should try to take it at the same time each day. Your doctor will determine the proper starting dose of hydroxyurea for you based on your weight and blood count. The dose will then be increased slowly to your maximum tolerated dose (maximum dose that does NOT produce severely low blood counts).Your doctor should measure your blood counts every two weeks after you begin treatment with hydroxyurea. Depending on the results, your dosage may be adjusted or the drug may be stopped for a while.

Hydroxyurea is a medication that must be handled with care. People who are not taking hydroxyurea should not be exposed to it. To decrease the risk of exposure, wear disposable gloves when handling hydroxyurea or bottles containing hydroxyurea. Anyone handling hydroxyurea should wash their hands before and after contact with the bottle or capsules. If the powder from the capsule is spilled, it should be wiped up immediately with a damp disposable towel and discarded in a closed container, such as a plastic bag. Hydroxyurea should be kept out of the reach of children and pets. Contact your doctor or pharmacist for instructions on how to dispose of outdated capsules.

Try not to miss your dose of hydroxyurea, but if you do, take it as soon as possible. If it is almost time for your next dose, skip the missed dose and resume your regular dosing schedule. Do not take two doses during the same day. If you miss more than one dose, call your doctor for instructions.

Take this medication exactly as prescribed by your doctor. Follow the directions on your prescription label carefully.

The dose your doctor recommends may be based on the following:

• actual or ideal weight, whichever is less
• how you respond to this medication
• your blood counts

If you accidentally take an overdose of hydroxyurea capsules, seek medical attention immediately. Contact your doctor, local Poison Control Center, or emergency room.

• Store hydroxyurea at room temperature in a tightly closed container.
• Keep this and all medicines out of the reach of children.

WARNING

Treatment of patients with hydroxyurea may be complicated by severe, sometimes life-threatening, adverse effects. Hydroxyurea should be administered under the supervision of a physician experienced in the use of this medication for the treatment of sickle cell anemia.

Hydroxyurea is mutagenic and clastogenic, and causes cellular transformation to a tumorigenic phenotype. Hydroxyurea is thus unequivocally genotoxic and a presumed transspecies carcinogen which implies a carcinogenic risk to humans. In patients receiving long-term hydroxyurea for myeloproliferative disorders, such as polycythemia vera and thrombocythemia, secondary leukemias have been reported. It is unknown whether this leukemogenic effect is secondary to hydroxyurea or is associated with the patient’s underlying disease. The physician and patient must very carefully consider the potential benefits of hydroxyurea relative to the undefined risk of developing secondary malignancies.