Hydroxyurea Side Effects

Medically reviewed by Drugs.com. Last updated on Jul 22, 2024.

Applies to hydroxyurea: oral capsule, oral tablet.

Precautions

It is very important that your doctor check your or your child's progress at regular visits to make sure that this medicine is working properly. Blood tests may be needed to check for unwanted effects.

Using this medicine while you are pregnant can harm your unborn baby. If you are a woman who can get pregnant, your doctor may do tests to make sure you are not pregnant before starting this medicine. Women should use an effective form of birth control during treatment with this medicine and for at least 6 months after the last dose. Men should use an effective form of birth control during treatment and for at least 1 year for Droxia® and Hydrea® and at least 6 months for Siklos® after the last dose to prevent pregnancy in a sexual partner. If a pregnancy occurs while using the medicine, tell your doctor right away.

Hydroxyurea can temporarily lower the number of white blood cells in your blood which increases the chance of getting an infection. It can also lower the number of platelets, which are necessary for proper blood clotting. If this occurs, there are certain precautions you can take, especially when your blood count is low, to reduce the risk of infection or bleeding:

• If you can, avoid people with infections. Check with your doctor immediately if you think you are getting an infection or if you get a fever or chills, cough or hoarseness, lower back or side pain, or painful or difficult urination.
• Check with your doctor immediately if you notice any unusual bleeding or bruising, black, tarry stools, blood in the urine or stools, or pinpoint red spots on your skin.
• Be careful when using a regular toothbrush, dental floss, or toothpick. Your medical doctor, dentist, or nurse may recommend other ways to clean your teeth and gums. Check with your medical doctor before having any dental work done.
• Do not touch your eyes or the inside of your nose unless you have just washed your hands and have not touched anything else in the meantime.
• Be careful not to cut yourself when you are using sharp objects such as a safety razor or fingernail or toenail cutters.
• Avoid contact sports or other situations where bruising or injury could occur.

Check with your doctor right away if you have back, leg, or stomach pains, bleeding gums, chills, dark urine, difficulty breathing, fever, general body swelling, headache, loss of appetite, nausea or vomiting, nosebleeds, pale skin, sore throat, unusual tiredness or weakness, or yellowing of the eyes or skin. These may be symptoms of a blood problem called hemolytic anemia.

Using this medicine for a long time may increase your risk of developing leukemia (cancer of the blood) or skin cancer. Use a sunscreen and protective clothing to protect your skin. Talk to your doctor if you have concerns about this risk.

If you had radiation treatment in the past, Hydrea® may cause your skin to become very red when you have radiation again. Tell your doctor right away if you have darkening or reddening of the skin.

While you are being treated with hydroxyurea, do not have any immunizations (vaccinations) without your doctor's approval. Live virus vaccinations (eg, nasal flu virus vaccine) should not be given while you are using hydroxyurea.

This medicine may increase your risk of having lung or breathing problems (eg, interstitial lung disease). Check with your doctor right away if you develop a fever, cough, or trouble breathing while using this medicine.

Make sure any doctor or dentist who treats you knows that you are using this medicine. You may need to stop using this medicine several days before you have medical tests.

Talk with your doctor before using this medicine if you plan to have children. Some men who use this medicine have become infertile (unable to have children).

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.

Serious side effects of hydroxyurea

Along with its needed effects, hydroxyurea may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking hydroxyurea:

Other side effects of hydroxyurea

Some side effects of hydroxyurea may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

For healthcare professionals

Applies to hydroxyurea: compounding powder, oral capsule, oral solution, oral tablet.

General adverse events

The more commonly reported adverse reactions among children have been infections and neutropenia. Among adults, hematologic, gastrointestinal symptoms, infections, headache, anorexia, and dry skin have been commonly reported.

Hematologic

• Very common (10% or more): Neutropenia (13%)
• Common (1% to 10%): Thrombocytopenia, anemia
• Postmarketing reports: Hemolytic anemia, macrocytosis^[Ref]

Gastrointestinal

• Common (1% to 10%): Nausea, upper abdominal pain, diarrhea, constipation
• Postmarketing reports: Stomatitis, vomiting, gastrointestinal ulcer, oral mucositis, pancreatitis^[Ref]

Pancreatitis has occurred when hydroxyurea was administered concomitantly with antiretroviral drugs, including didanosine and stavudine.^[Ref]

Other

• Common (1% to 10%): Fever, asthenia, pyrexia, fatigue, peripheral edema
• Postmarketing reports: Chills, malaise^[Ref]

Dermatologic

• Very common (10% or more): Dry skin (12%)
• Common (1% to 10%): Skin ulcer, alopecia
• Postmarketing reports: Skin ulceration, cutaneous lupus erythematosus, dermatomyositis-like skin changes, peripheral and facial erythema, nail hyperpigmentation, atrophy of skin and nails, scaling, violet papules, skin reactions (oral, ungula and cutaneous pigmentation), rash, melanonychia^[Ref]

Oncologic

• Frequency not reported: Leukemia, skin cancers^[Ref]

Leukemia secondary to long-term hydroxyurea has also been reported in patients with sickle cell disease. Leukemia has also been reported in patients with sickle cell disease and no prior history of treatment with hydroxyurea. Skin cancer has also been reported in patients receiving long-term hydroxyurea.^[Ref]

Genitourinary

• Common (1% to 10%): Urinary tract infection
• Postmarketing reports: Azoospermia, oligospermia, amenorrhea, dysuria^[Ref]

Nervous system

• Very common (10% or more): Headache (20%)
• Common (1% to 10%): Dizziness
• Frequency not reported: Peripheral neuropathy
• Postmarketing reports: Drowsiness, convulsions^[Ref]

Peripheral neuropathy has occurred when hydroxyurea was administered concomitantly with antiretroviral drugs, including didanosine and stavudine.^[Ref]

Hepatic

• Uncommon (0.1% to 1%): Hepatotoxicity, hepatic enzyme increased, cholestasis, hepatitis
• Frequency not reported: Both fatal and nonfatal hepatotoxicity have been reported in HIV-infected patients who received this drug in combination with antiretroviral agents^[Ref]

Respiratory

• Common (1% to 10%): Cough, lung disorder, dyspnea, nasopharyngitis
• Postmarketing reports: Diffuse pulmonary infiltrates, dyspnea, pulmonary fibrosis, interstitial lung disease, pneumonitis, alveolitis, allergic alveolitis^[Ref]

Metabolic

• Common (1% to 10%): Vitamin D deficiency, other metabolic and nutrition disorders, weight gain, increased weight
• Very rare (less than 0.01%): Tumor lysis syndrome
• Postmarketing reports: Anorexia, severe hypomagnesemia^[Ref]

Psychiatric

• Postmarketing reports: Hallucinations, disorientation^[Ref]

Renal

• Postmarketing reports: Elevations in serum uric acid, blood urea nitrogen (BUN), and creatinine levels^[Ref]

Hypersensitivity

• Postmarketing reports: Drug-induced fever

Drug-induced fever requiring hospitalization has been reported in the postmarketing period. It has been reported concurrently with gastrointestinal, pulmonary, musculoskeletal, hepatobiliary, dermatological or cardiovascular manifestations. Onset typically occurred within 6 weeks of initiation and resolved upon discontinuation of hydroxyurea. Upon re-administration fever reoccurred typically within 24 hours.

Immunologic

• Common (1% to 10%): Viral infections, bacterial infections, influenza
• Postmarketing reports: Systemic lupus erythematosus

Musculoskeletal

• Common (1% to 10%): Arthralgia, back pain, extremity pain

See also:

Further information

Hydroxyurea side effects can vary depending on the individual. Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Note: Medication side effects may be underreported. If you are experiencing side effects that are not listed, submit a report to the FDA by following this guide.

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