Siklos

Generic name: hydroxyurea [ hye-DROX-ee-yoo-REE-a ]
Brand names: Droxia, Hydrea, Siklos, Mylocel
Drug class: Antimetabolites

Medically reviewed by Drugs.com on Aug 9, 2023. Written by Cerner Multum.

What is Siklos?

Siklos is used to treat chronic myeloid leukemia, ovarian cancer, and certain types of skin cancer (squamous cell cancer of the head and neck).

Siklos is also used to reduce pain episodes and the need for blood transfusions in people with sickle cell anemia. This medicine will not cure sickle cell anemia.

Siklos may also be used for purposes not listed in this medication guide.

Siklos side effects

Get emergency medical help if you have signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Siklos may cause serious side effects. Call your doctor at once if you have:

• numbness, tingling, or burning pain in your hands or feet;

• skin numbness or purple discoloration;

• skin ulcers or open sores;

• sudden chest pain, wheezing, dry cough, feeling short of breath;

• low blood cell counts--fever, chills, tiredness, mouth sores, easy bruising, unusual bleeding, pale skin, cold hands and feet, feeling light-headed; or

• signs of liver or pancreas problems--loss of appetite, upper stomach pain (that may spread to your back), nausea or vomiting, fast heart rate, dark urine, jaundice (yellowing of the skin or eyes).

Common side effects of Siklos may include:

• loss of appetite, nausea;

• constipation, diarrhea;

• low blood cell counts;

• bleeding; or

• mouth sores.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Related/similar drugs

hydroxyurea, vitamin e, Endari, glutamine, Adakveo, Droxia

Warnings

Both men and women using Siklos should use birth control to prevent pregnancy. The use of Siklos by either parent may cause birth defects.

Using Siklos may increase your risk of developing other types of cancer, such as leukemia or skin cancer. Wear protective clothing and use sunscreen when you are outdoors.

Siklos can weaken your immune system. Call your doctor at once if you have a fever, chills, body aches, extreme tiredness, shortness of breath, bruising, or unusual bleeding.

Before taking this medicine

You should not use Siklos if you are allergic to it.

Tell your doctor if you have ever had:

• kidney disease (or if you are on dialysis);

• liver disease;

• a wound or ulcer on your leg;

• HIV or AIDS (especially if you take antiviral medicine);

• high levels of uric acid in your blood; or

• treatment with an interferon, chemotherapy, or radiation.

Using Siklos may increase your risk of developing other types cancer or leukemia. Talk with your doctor about your specific risk.

Siklos can harm an unborn baby. Both men and women using this medicine should use birth control to prevent pregnancy. The use of this medicine by either parent may cause birth defects.

• If you are a woman, keep using birth control for at least 6 months after your last dose of Siklos.

• If you are a man, keep using birth control for at least 1 year after your last dose (6 months if you took Siklos).

• Tell your doctor right away if a pregnancy occurs while either the mother or the father is using this medicine.

This medicine may affect fertility (ability to have children) in men. However, it is important to use birth control because Siklos may harm the baby if a pregnancy does occur.

You should not breastfeed while you are taking Siklos.

Older adults may be more sensitive to the effects of this medicine.

How should I take Siklos?

Follow all directions on your prescription label and read all medication guides or instruction sheets. Your doctor may occasionally change your dose. Use the medicine exactly as directed.

Siklos is usually taken once per day at the same time of day, with or without food. Swallow the pill whole with a glass of water.

Wash your hands before and after you handle Siklos or the bottle that contains the pills. For best protection, wear disposable gloves when handling the pills.

Do not open the Siklos capsule or crush or chew a tablet. Do not use a broken pill. The medicine from a crushed or broken pill can be dangerous if it gets in your eyes, mouth, or nose, or on your skin. If this occurs, wash your skin with soap and water or rinse your eyes with water.

If any powder from a broken pill is spilled, wipe it up at once with a damp paper towel and throw the towel away in a sealed plastic bag where children and pets cannot get to it.

Your doctor may also want you to take a folic acid supplement. Follow dosing instructions very carefully.

Siklos can lower your blood cell counts. Your blood will need to be tested often. Your cancer treatments may be delayed based on the results.

This medicine can affect the results of certain medical tests. Tell any doctor who treats you that you are using Siklos.

Store at room temperature away from moisture and heat. Keep the bottle tightly closed when not in use.

What happens if I miss a dose?

Take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.

Get your prescription refilled before you run out of medicine completely.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Overdose symptoms may include drowsiness, mouth sores, and swelling with pain and purple discoloration in your hands and feet.

What should I avoid while taking Siklos?

Using Siklos may increase your risk of developing skin cancer. Avoid exposure to sunlight or tanning beds. Wear protective clothing and use sunscreen (SPF 30 or higher) when you are outdoors.

Do not receive a "live" vaccine while using Siklos, or you could develop a serious infection. Live vaccines include measles, mumps, rubella (MMR), rotavirus, typhoid, yellow fever, varicella (chickenpox), zoster (shingles), and nasal flu (influenza) vaccine.

Avoid being near people who are sick or have infections. Tell your doctor at once if you develop signs of infection.

Do not handle Siklos pills or the medicine bottle without skin protection (disposable gloves).

What other drugs will affect Siklos?

Some medicines can increase your risk of serious side effects while taking Siklos. Tell your doctor if you are also using antiviral medicine or an interferon.

Other drugs may affect Siklos, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all your current medicines and any medicine you start or stop using.

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Medical Disclaimer

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