Hydroxyurea (Oral)


When patients are diagnosed with chronic myeloid leukemia (CML), their physician will devise a treatment plan based on their unique clinical presentation and medical history. Hydroxyurea is just one medication used to treat chronic myeloid leukemia, also known as cancer of the white blood cells.

CML occurs when myeloid cells grow at an increased rate in the patient's bone marrow and then accumulate in the patient's blood. Presenting in three phases, patients may be diagnosed with the condition when they're in a chronic or accelerated phase or when they are experiencing a blast crisis. If diagnosed early and treatment is begun during the chronic phase of CML, it is more likely that the patient will have a positive outcome.

Although CML may cured by a bone marrow or stem cell transport, there are various treatments which can be used to manage the disease. Hydroxyurea, for example, treats CML by inhibiting the production and replication of cells. When Hydroxyurea affects the unregulated and excessive amounts of myeloid cells, it can prevent them from increasing and allow the body to destroy them. As a result, Hydroxyurea can be used to stop CML from worsening and to reduce the number of rogue cells in the patient's body.

However, Hydroxyurea is not normally used alone when patients are treated for CML. The medication may be used alongside tyrosine kinase inhibitors in order to increase the efficacy of treatment. In addition to this, Hydroxyurea may be used in conjunction with radiation treatment in patients who are being treated for neck and/or head cancer.

Whilst Hydroxyurea can be used to treat certain cancers, it is also used in the treatment of sickle cell anemia. When patients are affected by this condition, the hemoglobin in their red blood cells is abnormal in shape. Red blood cells can become more rigid when the condition is present and may lead to the patient experiencing intense pain. In addition to this, sickle cell anemia can cause swelling of the feet and hands, as well as anemia. Patients may also have an increased risk of suffering a stroke or developing bacterial infections when sickle cell anemia is untreated.

When Hydroxyurea is used to treat patients with sickle cell anemia, the medication increases the rate at which fetal hemoglobin is produced. When more fetal hemoglobin is present, the patient's red blood cells are less likely to take on an abnormal shape and their symptoms should be reduced. Similarly, the patient's white blood cell count is reduced via treatment with Hydroxyurea and this can reduce the inflammation associated with the condition.

Although Hydroxyurea has been used for some time, it is still effective in treating patients with chronic myeloid leukemia and sickle cell anemia, as well as those with head and neck cancers. When used in conjunction with other treatments, Hydroxyurea can help to reduce the patient's symptoms and can be used to treat their condition effectively.

Conditions Treated

Side Effects

When taking medication, patients may experience some side-effects. In most cases, physicians will warn patients about the most common side-effects associated with Hydroxyurea and advise patients how to reduce any side-effects which do occur. Often, side-effects are most prolific when the patient begins taking a new medication and are reduced over time.

If patients notice the following side-effects when they first start taking Hydroxyurea, they will not necessarily require medical intervention:

  • Diarrhea
  • Constipation
  • Drowsiness
  • Nausea or vomiting
  • Loss of appetite
  • Rash on skin
  • Itching
  • Redness of skin at the place of radiation

Although patients may not require medical assistance if the above side-effects are fairly mild, they should not hesitate to seek medical help if their side-effects are severe, prolonged or distressing.

Patients should also seek immediate medical advice if they experience the following side-effects when taking Hydroxyurea:

  • Cough or hoarseness
  • Difficult or painful urination
  • Chills or fever
  • Pain in lower back or side
  • Tarry, black stools
  • Red, pinpoint spots on skin
  • Blackening of the toenails and fingernails
  • Confusion
  • Blood in stools or urine
  • Sores on the lips or in the mouth
  • Convulsions or seizures
  • Unusual bruising or bleeding
  • Dizziness
  • Pain in joints
  • Headache
  • Feeling, hearing or seeing things that are not there
  • Bleeding under the skin
  • Swelling of the lower legs or feet
  • Weight loss
  • Blisters on the skin
  • Unusual weakness or tiredness
  • Itching skin
  • Pale or bluish color on the skin of the toes or fingers
  • Pain in the toes or fingers
  • Coldness of the toes or fingers
  • Tingling or numbness of the toes or fingers
  • Crater-like lesions on the skin

If patients experience any other side-effects when using Hydroxyurea, they should seek also seek medical advice.


When patients are treated with Hydroxyurea, their dose will depend on their condition, their clinical presentation and their medical history, as well as their age and weight.

Generally, if patients are given Hydroxyurea for the treatment of head and neck cancer or chronic myeloid leukemia, they will be advised to take 15 mg per kilogram of bodyweight per day. In most cases, patients will be instructed to take their daily dose of Hydroxyurea as a single dose. However, the patient's dose of Hydroxyurea may be increased once the efficacy of the treatment and their response to the medication has been assessed.

If patients are prescribed Hydroxyurea for the treatment of sickle cell anemia, they may also be instructed to take 15mg per kilogram of body weight per day. Although the patient's dose of Hydroxyurea may be increased, patients with sickle cell anemia are not normally prescribed more than 35mg of Hydroxyurea per kilogram of bodyweight per day.

If patients forget to take a dose of Hydroxyurea, they should take the medication as soon as they remember to do so. However, if their next dose is almost due, patients will need to skip the missed dose and continue with their regular treatment schedule. Patients should not attempt to take a double dose of Hydroxyurea, even if an earlier dose of medication has been missed.

As Hydroxyurea is a potent drug, patients will need to take precautions when handling their medication. Ideally, they should not touch Hydroxyurea when they are being treated with it. Patients should, therefore, wear disposable gloves when handling their medication or the bottle it comes in. Patients should wash their hands thoroughly both before and after administering a dose of Hydroxyurea or before and after handling the medicine container.

If patients accidentally touch a Hydroxyurea capsule, they should wash their hands immediately. Similarly, if the contents of a capsule comes into contact with the patient's eye, they should rinse their eyes with an isotonic eyewash or water for at least fifteen minutes.

If a Hydroxyurea capsule is accidentally spilt, patients should use a disposable cloth to wipe up the medicine. This should be done immediately after the spillage has occurred. Patients should then place the empty or remaining capsule into a closed container, along with any cleaning material they have used. Following this, patients should clean the area in which the medication was spilled at least three times, using water, detergent and protective gloves each time.

Due to the dangers of touching the medicine, patients should be taught how to administer their medication when it is prescribed. If patients are unsure how to take Hydroxyurea or when to take their medication, they should contact their physician or pharmacist for advice.

Potential Drug Interactions

As some medications can interact with one another, it may not be safe for them to be prescribed at the same time. For example, using Hydroxyurea alongside the following medications is not recommended:

Similarly, taking Hydroxyurea at the same time as the following medicines is not usually advised:

  • Adenovirus Vaccine
  • Cholera Vaccine, Live
  • Bacillus of Calmette and Guerin Vaccine, Live
  • Yellow Fever Vaccine
  • Didanosine
  • Typhoid Vaccine
  • Stavudine
  • Influenza Virus Vaccine, Live
  • Smallpox Vaccine
  • Poliovirus Vaccine, Live

Although physicians do not normally recommend taking Hydroxyurea alongside the above medications, it may be appropriate in some situations. If patients are given Hydroxyurea in conjunction with the above medicines, their dose may be modified to try and prevent an interaction taking place.

Hydroxyurea could also interact with over-the-counter medicines, supplements and vitamins. Due to this, patients should tell their physician if they are taking any of these substances before they start using Hydroxyurea. In addition to this, patients should obtain medical advice before using any new medicines, supplements or vitamins once they have begun using Hydroxyurea.


If patients have existing health problems or a history of a certain condition, it may affect their treatment with Hydroxyurea. Due to this, patients should disclose their full medical history to their physician before beginning treatment. The following conditions may be particularly relevant to treatment with Hydroxyurea:

  • Kidney disease
  • Anemia
  • Low platelet levels in blood (Thrombocytopenia)
  • Low levels of white blood cells (Leukopenia)
  • HIV infection
  • Bone marrow problems

During treatment with Hydroxyurea, patients will need to attend regular consultations with their doctor to ensure the medication is working as intended and isn't having any harmful effects.

When taking Hydroxyurea, the patient's level of white blood cells can be temporarily lowered. Due to this, patients may be more likely to contract an infection. In order to minimize this risks, patients should avoid anyone who they know to be ill and should seek medical assistance if they feel unwell.

Patients may also have a low platelet count whilst they are receiving treatment with Hydroxyurea. They may, therefore, be more at risk of developing an infection or experiencing bleeding. Patients should obtain immediate medical help if they experience uncontrolled bleeding whilst taking this medicine. Patients should refrain from taking part in contact sport and be particularly careful when using razors and/or fingernail clippers. Patients should also seek help from their dentist is they experience bleeding gums whilst taking this medicine.

Patients should also seek immediate medical help if they experience any of the following whilst taking Hydroxyurea:

  • Tarry, black stools
  • Unusual bruising or bleeding
  • Blood in stools or urine
  • Red, pinpoint spots on skin

If the patient is due to undergo any medical tests or procedures, they should inform that their physician that they are taking Hydroxyurea in advance. This includes any dental work they are due to undergo. In some instances, patients may be advised to stop taking Hydroxyurea a few days before the procedure.

Using Hydroxyurea for a long period of time may increase the patient's risk of developing skin cancer and/or leukemia. Patients should wear protective clothing and use sunscreen to reduce this risk and should contact their doctor for advice if they are concerned about this risk.

If patients have undergone radiation therapy in the past, Hydroxyurea may cause their skin to become very red when they undergo radiation again. If patients notice their skin darkening or becoming red, they should notify their doctor immediately.

Whilst taking Hydroxyurea, patients should not have any vaccinations or immunizations without their doctor's express approval. Live vaccines should not be given whilst the patient is being treated with Hydroxyurea.

If Hydroxyurea is given to patients who are pregnant, it may harm their unborn baby. Due to this, patients who are pregnant are not usually treated with this medication. Female patients should use an effective contraception whilst taking Hydroxyurea and for at least six months after their treatment. Male patients should also use effective birth control whilst receiving treatment with Hydroxyurea and for at least one year afterwards.

If pregnancy occurs whilst either partner is taking Hydroxyurea, patients should contact their physician immediately.

When patients are prescribed Hydroxyurea, they should discuss their fertility with their doctor. If they plan to have children in the future, it is particularly important that they notify their physician. Hydroxyurea has been known to cause infertility in male patients and may affect the patient's fertility in the future.

Some medications can be passed on to an infant via breastfeeding. Due to the risks associated with Hydroxyurea, patients are normally advised not to breastfeed whilst taking Hydroxyurea or for some time after their treatment has finished. Patients should obtain medical advice before breastfeeding if they have been treated with Hydroxyurea in the past.

Before taking Hydroxyurea, patients should tell their doctor if they are allergic to any substances. This includes allergies to medicines, animals, preservatives, dyes and/or foods. If patients experience an allergic reaction when taking Hydroxyurea, they will need emergency medical attention. An allergic reaction may include the following symptoms:

  • Wheezing
  • Shortness of breath
  • Difficulty swallowing
  • Difficulty breathing
  • Hives
  • Swelling of the hands, face, lips, tongue, throat and/or mouth
  • Itching
  • Rash on the skin
  • Hoarseness


When storing Hydroxyurea at home, patients should take extra precautions to ensure that the medication is secure and that it won't be handled by anyone who isn't wearing protective, disposable gloves. It is particularly important that children and/or animals cannot access the medicine.

In order to store Hydroxyurea safely, patients should follow the medication guide given to them when they were prescribed the medicine. In general, Hydroxyurea can be kept at room temperature but should be kept away from direct light, heat and/or moisture.

If patients are advised to stop using this medicine or if it reaches its use-by date, they will need to dispose of it carefully. Hydroxyurea should never be thrown out with regular household waste as it may cause harm to other people.

Instead, patients should contact their physician's office or pharmacist and ask how to dispose of their medication. In most cases, there will be a designated medical waste service for patients to use.


Although Hydroxyurea was once a first-choice medicine for the treatment of chronic myeloid leukemia, tyrosine kinase inhibitors are now used more often. However, Hydroxyurea may be used alongside tyrosine kinase inhibitors and radiation therapy. When used in conjunction with these other forms of treatment, Hydroxyurea can be extremely effective in treating CML and can drastically increase survival rates.

When used to treat sickle cell anemia, Hydroxyurea can have a positive effect on patients and can greatly reduce their symptoms. By preventing their red blood cells from developing into an abnormal shape, Hydroxyurea can prevent patients from experiencing a sickle cell crisis or attack.

As Hydroxyurea can be used to treat various different conditions, it's commonly prescribed and has been used with success. Although the medication can have a number of serious and long-term side-effects, it can also be used to successfully prolong life. Whilst the risks of using this medication must be assessed before treatment begins, the benefits of treatment with Hydroxyurea often outweigh the potential harm which can be caused.