Hydroxyurea was first synthesized in 1869 and is presently
being used to treat a multitude of conditions, including sickle cell disease. Hydroxyurea
reduces the severity of sickle cell disease by stimulation the production of fetal
hemoglobin, or HbF.
HbF is the form of hemoglobin present in the fetus and small
infants. Although some may persist, most HbF disappears early in childhood.
Fetal hemoglobin is able to block the sickling action of red blood cells and because
of this infants with sickle cell disease do not develop symptoms of the illness
until HbF levels have dropped. Adults who have sickle cell disease but still
retain high levels of hemoglobin F generally have a mild form of the disease.
Hydroxyurea is recommended as frontline therapy to treat
adults and adolescents with moderate-to-severe recurrent pain. Hydroxyurea
reduces the frequency of acute pain crises and episodes of acute chest syndrome.
It is taken daily by mouth and can be taken indefinitely and the benefits
appear to be long-lasting.
Not all patients respond to hydroxyurea, and the best
candidates for the treatment are not yet clear. Many patients who can benefit
from it are not receiving it. Hydroxyurea is still being investigated for
younger patients. To date, the response to the drug in children with sickle
cell disease is similar to the response in adults, and few severe adverse
effects are being reported. Recent research also suggests that hydroxyurea is
safe for infants.
Side effects include constipation, nausea, drowsiness, hair
loss, and inflammation of the mouth. More severe side effects include reduction
of white blood cells, called neutropenia, and clot-forming platelets, or thrombocytopenia.
Hydroxyurea should not be taken by pregnant patients as it can cause birth
defects. There have been concerns that long-term use of hydroxyurea may
increase the risk of developing leukemia, but the significance of this risk
remains unclear.
The recommended dose for sickle cell patients is 15mg/kg body weight for this drug. One other side effect of this drug that was not mentioned is that it can cause an imbalance in liver enzymes, and may be associated with liver disease. Thus, drug consumption must be monitored by the physician to make sure no liver function is lost. Cool article!
ReplyDeleteNot all people with sickle cell disease are eligible to participate with the hydroxyurea therapy. Any patient who has more than three pain crises in one year and symptomatic anemia with alloimmunization are eligible. In addition, the persistent occurrences of priapism despite standard therapy, creatinine levels < 1.7 mg, and a retic count of > 150,000 average value are eligible to receive the hydroxyurea therapy. Patients should also be warned of routine side effects of hydroxyurea prior to starting the medication.
ReplyDeleteI knew there was treatment being developed by doctors using gene therapy but I didn't know that stimulating HgbF production was used as one as well. As far as it being used in children, some hospital centers such as Children's Hospitals in Boston , Philadelphia, and Oklahoma,and Duke University Hospital all have been drafted to be a part of the NHLBI's Pediatric Study of Hydroxyurea in Sickle Cell disease. I really believe that this drug is the best treatment thus far, but I can't wait to see the comparisons between hydroxyurea and once developed, the gene therapy.
ReplyDeleteI found it interesting that this drug is also used to treat certain cancers such as melanoma, CML, and inoperable ovarian cancer, yet the drug itself increases the risk of developing cancer. Patients who take the drug should make sure they take all risks into consideration before using the drug and should have regular check-ups with their physician.
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