Medications for Sickle Cell Disease

There are now 4 medicines that have been approved by the U.S. Food and Drug Administration (FDA) to treat sickle cell disease (SCD). Hydroxyurea was the only 1 available until 2017, and is still the most common and studied treatment for sickle cell disease.

Since 2017, 3 new medications – Endari, Adakveo, and Oxbryta – have been approved. Like hydroxyurea, Endari and Adakveo reduce the frequency of pain crises. Oxbryta reduces anemia (low red blood cell count). These medications can be used alone or with hydroxyurea.

Another common treatment is folic acid, either in foods or as a supplement. Many doctors recommend daily folic acid supplements to treat anemia.

Hydroxyurea

Hydroxyurea has been used to treat SCD since the 1980s. The FDA approved it to treat adults with SCD in 1998 and to treat children with SCD in 2017. It is also used to treat some forms of cancer. However, doctors use a lower dose to treat SCD.1

Hydroxyurea helps reduce sickling of red blood cells, mostly by increasing your fetal hemoglobin levels. Fetal hemoglobin protects newborns from the effects of sickle hemoglobin. As people age, the amount of fetal hemoglobin decreases and complications begin. Increasing fetal hemoglobin levels reduces clumping of sickle hemoglobin and helps keep your red blood cells round and flexible.2,3

Hydroxyurea reduces many problems caused by SCD. For example, people with SCD who take hydroxyurea have fewer:2–4

  • Pain crises
  • Acute chest syndrome episodes
  • Blood transfusions
  • Hospital stays

Access and cost limit hydroxyurea use for many people, especially in lower-resource areas. There are also misconceptions that it causes cancer. Mild side effects are possible, but there is no evidence of hydroxyurea causing any long-term health problem.1,5

Hydroxyurea may increase the risk of birth defects. If you are planning to have a baby, talk to your doctor. Pregnant women with sickle cell disease should decide with their doctor whether or not to stop taking hydroxyurea during pregnancy.1,4

Endari (L-glutamine)

Endari was the first treatment approved for children with SCD and the first new treatment for adults in nearly 20 years. Endari was approved in 2017 to treat SCD in people 5 years of age and older.6

Endari contains an amino acid called glutamine. When glutamine circulates in the blood, it gets taken up by sickle cells and produces antioxidants. Antioxidants help neutralize toxic chemicals that cause red blood cells to become rigid and sickle-shaped. This helps sickle cells regain flexibility and flow better through blood vessels.6,7

Endari reduces the number of disease crises. People who take Endari also have fewer and shorter hospital stays. The twice-daily powder form may be more challenging than the once-daily hydroxyurea tablets. However, it is a non-chemotherapeutic option with minimal side effects.6,7

Oxbryta (Voxelotor)

Oxbryta is an oral treatment approved in 2019 for people 12 years of age and older. It increases the ability of hemoglobin to bind to oxygen. When hemoglobin is bound to oxygen, it does not clump together inside red blood cells. This helps prevent red blood cells from sickling and bursting too soon (hemolysis).4,8

Oxbryta increases hemoglobin levels and lowers bilirubin levels. This means that Oxybryta reduces hemolysis and anemia. Oxbryta may also treat jaundice, which is a symptom of anemia. Common side effects include headaches, diarrhea, and fatigue.8

Adakveo (Crizanlizumab)

The FDA approved Adakveo in 2019 to treat SCD in people 16 years of age and older. Adakveo contains an antibody (a protein designed to bind to a specific molecule in the body). Adakveo binds to P-selectin, which is a protein on cells that line blood vessel walls. P-selectin sticks sickle cells to blood vessel walls.4,9

Adakveo blocks P-selectin to prevent sickle cells from sticking to blood vessel walls. This helps maintain normal blood flow and reduce pain. It reduces the frequency of acute episodes and the length of hospital stays.9

People usually receive 2 doses in the first month of treatment, then Adakveo is given monthly by infusion into the bloodstream. Possible side effects include joint pain, diarrhea, and itching. Ongoing clinical trials are evaluating the success of Adakveo to treat children and specific complications.9

Folic Acid

Folate is a vitamin that bone marrow needs to make new red blood cells. Folate deficiency can lead to anemia. Our bodies do not make folate, so we must get it from food. Many foods have folate, including vegetables, fruit, and nuts.10

Folic acid can be used as a dietary supplement because it is converted into folate by the body. People with SCD often have low levels of folate because of the high turnover of red blood cells. Folic acid supplements can increase hemoglobin levels and red blood cell count.10

There is not much evidence that folic acid reduces symptoms or treats SCD. Many doctors still recommend taking daily supplements because it may prevent worsening anemia from folate deficiency. Talk to your doctor about folic acid and other vitamins, and ask what types of foods to include in your diet.10-12

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Written by: Matthew Zajac | Last reviewed: January 2021