Hydroxyurea: Mechanism of Action, Side Effects, Interactions, Precautions, Dose and Important Considerations

It is a medication used to treat myeloid leukemia and cancers of the head and neck.

Hydroxyurea is a prescription medicine. It comes in two presentations; capsules and tablets.

Mechanism of action

Hydroxyurea belongs to a class of medications called antimetabolites.

Hydroxyurea substitutes some parts that cancer cells need to grow in people with cancer.

Cancer cells absorb hydroxyurea, which prevents the cancer cell from growing. Cancer cells grow faster than normal cells, so they are more affected by the drug.

In people with sickle cell disease, this medication changes the shape of red blood cells. This makes sickle cell crises less likely to occur.

Side effects of hydroxyurea

The oral hydroxyurea capsule may cause dizziness and drowsiness during the first hours after taking it. These side effects are more likely to occur when you start treatment or when your doctor increases the dose.


The most common side effects include:

  • Stomach ache.
  • Constipation.
  • Diarrhea.
  • Nausea.
  • Vomiting
  • Loss of appetite

If these effects are mild, they may disappear in a few days or a couple of weeks. If they persist, talk to your doctor.

Serious side effects

Call your doctor immediately if you have serious side effects such as:


Symptoms may include:

  • More frequent infections than usual.
Skin cancer

Symptoms may include:

  • Changes in the color and texture of the skin.
  • New polka dots
  • Protuberances on your skin
Damage to blood vessels

Symptoms may include:

  • Develop open sores on your arms or legs.


The oral hydroxyurea capsule may interact with other medications, vitamins, or herbs you may be taking.

Medications against HIV:

Taking didanosine or stavudine with hydroxyurea increases the risk of damage to the pancreas and liver. You also have an increased risk of nerve pain.


Allergy warning: Hydroxyurea can cause a severe allergic reaction. Symptoms may include:

  • Difficulty breathing.
  • Swelling of your throat or tongue.

Call your doctor or go to the nearest emergency room if you develop these symptoms.

Warnings for pregnant women:  Hydroxyurea can harm the fetus. This is based on the findings of animal studies and our knowledge of how medicine works.

Women of childbearing age who take this medication should use an effective contraceptive method during treatment and at least six months after stopping it.

Men who use this medication should use an effective contraceptive method during treatment and at least one year after stopping it.

Warnings for breastfeeding women:  Hydroxyurea can pass into breast milk and cause side effects in a breastfed child who is breastfedbreastfed. It would help if you stopped breastfeedingbreastfeeding when you take hydroxyurea.

Talk to your doctor if you breastfeed.

Warnings for seniors: If you are over 65, your body may be more sensitive to this medication. Your doctor may ask you to take a low dose.

Warnings for children: This medicine has not been studied in children. It should not be used in children under 18 years of age.

Hydroxyurea dose

The dosage, form of medication, and how often you take the drug will depend on:

  • Your age.
  • The condition that is being treated.
  • How serious is your situation?
  • Other medical conditions have how you react to the first dose.

This medicine must be taken as prescribed by your doctor. If you do not take the medication as prescribed by your doctor, you run risks.

If you stop taking the medication suddenly or do not take it, your cancer cells may quickly divide, or your sickle cells may return to your sickle shape. These effects can cause more severe tumors in people with cancer.

What happens if you take too much hydroxyurea?

It could have dangerous levels of the drug in your body. Symptoms of an overdose of this medication may include:

  • Mouth ulcers
  • Swelling or flaking of your hands and feet.
  • Darkening of your skin.

Call your doctor or the local poison control center if you think you have taken too much of this medication.

How to know if the medicine is working?

You may not feel anything different. If you take this medicine for cancer, your doctor may check your cancer cell number.

If you are taking this medicine for sickle cell disease, your doctor can check the shape of your red blood cells. This information will help your doctor determine if this medication is working.

Important considerations for taking hydroxyurea

Consider these considerations if your doctor prescribes hydroxyurea:

  • You can take hydroxyurea with or without food.
  • Do not cut or crush the capsule.
  • Store the generic hydroxyurea at room temperature between 20 ° C and 25 ° C.
  • Keep all pills away from light.
  • Do not store this medication in damp or humid areas, such as bathrooms.


SCopeheal has made every effort to ensure that all information is objectively correct, complete, and up-to-date. However, this article should not be used as a substitute for the knowledge and experience of a licensed health professional.