What is Hydroxyurea?
Hydroxyurea (pronounced hy-DROK-see-yoo-REE-uh) was originally approved by the U.S. Food and Drug Administration (FDA), the agency responsible for reviewing and approving drugs, in 1967.
Research into using hydroxyurea to treat sickle cell disease would eventually lead FDA to approve its use in 1998. But the approval was for adults with sickle cell disease and not for children.
On December 21, 2017, FDA approved hydroxyurea to reduce the frequency of painful crises and the need for blood transfusions in pediatric patients 2 years of age and older with sickle cell anemia with recurrent moderate to severe painful crises: this is Siklos®.
What is Siklos®?
Siklos® is the only FDA-approved prescription medicine that is used to reduce the frequency of painful crises and reduce the need for blood transfusions in adults and children, 2 years of age and older, with sickle cell anemia with recurrent moderate to severe painful crises.
It is not known if Siklos® is safe and effective in children less than 2 years of age.
This is the first FDA approval of hydroxyurea for use in pediatric patients with sickle cell disease.
Siklos® can accompany growing patients into adulthood as Siklos® is now approved for adults.
Siklos® can lessen the frequency of pain for patients with sickle cell disease
Individuals with sickle cell disease experience “painful crises” when their sickle-shaped red blood cells block their blood vessels, preventing blood and oxygen from reaching their tissues and causing pain. Painful crises may result in hospitalization and require pain medication. A sickle cell crisis can also damage tissues and cause organ failure, such as liver or kidney failure.
Siklos® was studied in children from 2-18 years of age with sickle cell disease. After 12 months of hydroxyurea treatment, the percentage of children who had at least one painful crisis, one episode of pneumonia, one hospitalization due to sickle cell disease or one blood transfusion, decreased.
Siklos was also studied in adults with sickle cell disease. After 12 months of Siklos treatment, the episodes of painful crises, hospitalizations, acute chest syndrome and blood tranfusions decreased.
Why Siklos®?
- Siklos® has been studied and proven safe and effective for adults patients 2 years of age and older.
- Siklos® is the only hydroxyurea-based treatment of its kind specifically indicated and approved for patients 2 years of age and older.
- With Siklos®, your child’s healthcare provider can tailor your child’s dose to his/her weight.
- Siklos® tablets can be dissolved in water if your child has trouble swallowing them whole.
- Siklos® is now approved for adults.
Ask your healthcare provider about Siklos® today.
How Siklos® Helps
Science does not fully understand how hydroxyurea works, but studies suggest that it increases the amount of fetal hemoglobin (HbF), as well as the amount of water, in red blood cells. In this way, Siklos® helps keep red blood cells round and flexible so they can travel more easily through the blood vessels. This may help reduce painful crises and some of the complications of the disease.
Babies are born with HbF to help protect them from health problems during their first few months of life. HbF helps prevent red blood cells from changing into a sickle shape.
In most people, the amount of HbF decreases after the first few months of life. Some people have more HbF than others. People with sickle cell disease who have higher levels of HbF may experience fewer complications of the disease.
For Siklos® to help, it must be taken every day, at the same time each day, with a glass of water, exactly as instructed by your or your child's healthcare provider.
It may take up to a year or more before you or your child's feels the full benefits of Siklos® because the dose must be adjusted gradually until the right dose is reached. Therefore, you or your child will require continuous follow-up appointments with your or your child's healthcare provider throughout treatment.
Safety Information about Siklos®
Pediatric Patients with Sickle Cell Disease
The safety of Siklos® was established in pediatric patients aged 2-18 years with sickle cell anemia with recurrent moderate to severe painful crises. Use of Siklos® in these age groups is supported by evidence from a reliable scientific study (known as the ESCORT-HU). 405 pediatric patients ages 2 to under 18 were enrolled. Among the 405 pediatric patients treated with Siklos® in this study, 274 were children (2-11) and 108 were adolescents (12-16).
It is not known if Siklos® is safe and effective in children less than 2 years of age.
There are serious risks associated with taking Siklos®. The most common risks are infections as a result of low blood cell counts, including low red blood cells, white blood cells, and platelets. Some people have developed cancer, such as leukemia and skin cancer, after taking Siklos® for a long time. Your healthcare provider will check you for cancer. You should protect your skin from the sun using sunblock, hats, and sun-protective clothing. These are not all the risks. For this reason, your child will need regular blood tests to check blood counts. If white blood cell count is low, his/her healthcare provider may lower the dose of Siklos® or stop treatment until levels return to normal.
Your child should avoid unnecessary or prolonged sun exposure to sunlight and wear protective clothing and sunscreen.
You and your child’s healthcare provider will decide if Siklos® is right for your child.
Adult Patients with Sickle Cell Disease
Siklos was also studied in adults with sickle cell disease. After 12 months of Siklos treatment, the episodes of painful crises, hospitalizations, acute chest syndrome and blood tranfusions decreased.
Use of Siklos in adults is supported by evidence from a reliable scientific study (known as ESCORT-HU). 1077 adult patients were enrolled in this study.
There are serious risks associated with taking Siklos. The most common risks are infections, headaches, and dry skin.
Other possible risks include low blood cell count and cancer. These are not all the risks. For this reason, your healthcare provide will need regular blood tests to check blood counts.
Indication
Siklos® is a prescription medicine that is used to reduce the frequency of painful crises and reduce the need for blood transfusions in adults and children, 2 years of age and older, with sickle cell anemia with recurrent moderate to severe painful crises.
What is the most important information I should know about SIKLOS?
SIKLOS can cause serious side effects including:
- Low blood cell counts are common with SIKLOS, including low red blood cells, white blood cells, and platelets, and can be severe and life-threatening. If your white blood cell count becomes very low, you are atincreased risk for infection. Your healthcare provider will check your blood cell counts before and every 2 weeks during treatment with SIKLOS. Your healthcare provider may change your dose or tell you to stop taking SIKLOS if you have low blood cell counts. Tell your healthcare provider right away if you get any of the following symptoms:
- fever or chills
- shortness of breath
- body aches
- unusual headache
- feeling very tired
- bleeding or unexplained bruising
- Cancer. Some people have developed cancer, such as leukemia and skin cancer, after taking SIKLOS for a long time. Your healthcare provider will check you for cancer. You should protect your skin from the sun using sunblock, hats, and sun-protective clothing.
- SIKLOS can harm your unborn baby.
For females taking SIKLOS who can become pregnant:- You should talk with your healthcare provider about the risks of SIKLOS to your unborn baby.
- You should use effective birth control during treatment with SIKLOS and for at least 6 months after treatment with SIKLOS.
- Your healthcare provider will perform a pregnancy test before you start treatment with SIKLOS. Tell your healthcare provider right away if you become pregnant or think you may be pregnant.
SIKLOS may cause fertility problems in males. Talk to your healthcare provider if this is a concern for you.
See “What are the possible side effects of SIKLOS?” for more information about side effects.
What is SIKLOS?
SIKLOS is a prescription medicine that is used to reduce the frequency of painful crises and reduce the need for blood transfusions in adults and children, 2 years of age and older, with sickle cell anemia with recurrent moderate to severe painful crises.
It is not known if SIKLOS is safe and effective in children less than 2 years of age.
Do not take SIKLOS if you are allergic to hydroxyurea or any of the ingredients in SIKLOS. See the end of this Medication Guide for a list of the ingredients in SIKLOS.
Before taking SIKLOS, tell your healthcare provider about all of your medical conditions, including if you:
- have kidney problems or are receiving hemodialysis
- have liver problems
- have human immunodeficiency virus (HIV) or take HIV medicines. Taking SIKLOS with certain HIV medicines can cause serious reactions and may lead to death.
- have increased levels of uric acid in your blood (hyperuricemia)
- have a history of receiving interferon therapy or are currently receiving interferon therapy
- have leg wounds or ulcers
- plan to receive any vaccinations. You should not receive “live vaccines” during treatment with SIKLOS.
- are pregnant or plan to become pregnant. See “What is the most important information I should know about SIKLOS?”
- are breastfeeding or plan to breastfeed. It is not known if SIKLOS can pass into your breast milk. Do not breastfeed during treatment with SIKLOS.
Tell your healthcare provider about all the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements.
How should I take SIKLOS?
Read the Instructions for Use at the end of this Medication Guide for step-by-step instructions on how to prepare a dose of SIKLOS. If you have any questions, talk to your healthcare provider or pharmacist.
- Take SIKLOS exactly as your healthcare provider tells you to take it.
- Take SIKLOS 1 time a day at the same time each day.Take SIKLOS exactly as your healthcare provider tells you to take it.
- Take SIKLOS 1 time a day at the same time each day.
- Swallow the tablet(s) with a glass of water. If you are not able to swallow SIKLOS tablets, you can dissolve your prescribed dose in a small amount of water in a teaspoon and swallow right away.
- SIKLOS is supplied as 100 mg tablets and 1,000 mg tablets. The SIKLOS tablets have separation lines (score lines) and can be broken at these score lines to provide smaller doses.
- Each 100 mg tablet can be divided into 2 equal parts (each part is 50 mg).
- Each 1,000 mg tablet can be divided into 4 equal parts (each part is 250 mg).
- Your healthcare provider will tell you how many tablets or parts of a tablet you should take.
- SIKLOS tablets must be handled with care. To decrease the risk of exposure, you or your caregivers should do the following when handling SIKLOS:
- Wear disposable gloves when handling SIKLOS or bottles containing SIKLOS. Wash your hands with soap and water before and after handling SIKLOS tablets or bottles containing SIKLOS.
- Avoid contact with crushed tablets. If contact with crushed tablets happens on the skin, wash the skin area right away and thoroughly with soap and water. If contact with crushed tablets happens in the eyes, flush the eyes thoroughly with water or isotonic eyewash used for that purpose for at least 15 minutes.
- Powder spilled from the broken tablet should be wiped up with a damp disposable towel which must be thrown away in a closed container such as a plastic bag to avoid ingestion of powder by other people. The spill areas should then be cleaned using a detergent solution followed by clean water.
- If you take too much SIKLOS, call your healthcare provider or go to the nearest hospital emergency room right away.
What are the possible side effects of SIKLOS?
SIKLOS may cause serious side effects, including:
See “What is the most important information I should know about SIKLOS?”
- Skin ulcers, including leg ulcers, and death of skin tissue (gangrene) have happened in people who take SIKLOS. This has happened most often in people who receive interferon therapy or have a history of interferon therapy. Your healthcare provider will decrease your dose or stop treatment with SIKLOS if you develop any skin ulcers.
- Enlarged red blood cells (macrocytosis). Macrocytosis is common in people who take SIKLOS and can make it difficult to detect a decrease of folic acid. Your healthcare provider may prescribe a folic acid supplement for you.
- Hemolytic Anemia, the fast breakdown of red blood cells, has happened in people who take SIKLOS. Tell your healthcare provider if you develop yellowing of your skin (jaundice) or blood in your urine. Your healthcare provider may do blood tests if you have persistent or worsening anemia not related to sickle cell anemia.
The most common side effects of SIKLOS in children include:
- infections
- low white blood cells
The most common side effects of SIKLOS in adults include:
- infections
- headache
- dry skin
These are not all the possible side effects of SIKLOS.
Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.