No cure for sickle cell anemia exists. Treatment centers on controlling infection, maintaining hydration and teaching patients how to prevent disease complications. Hydroxyurea is a cancer drug that sickle cell patients take regularly to prevent episodes of sickle cell crisis. Hydroxyurea has no therapeutic effect when taken during severe pain episodes and sickle cell crisis. The most dangerous side effects of hydroxyurea result from the drugs suppression of bone marrow function.
Infection
Bone marrow suppression decreases the production of red blood cells, white blood cells and platelets. White blood cells are essential for proper immune system function. Leukopenia, or a low number of white blood cells, places a person at risk for infection. The National Heart, Lung and Blood Institute states that infections like pneumonia and influenza can be fatal to sickle cell anemia patients. "Pearson Nurse's Drug Guide 2010" reports that sickle cell patients require weekly blood draws to monitor white blood cell counts. If white blood cells drop below 2,500 per millimeter cubed, physicians stop hydroxyurea until blood cell counts recover.
Mouth Sores
Hydroxyurea interferes with a cell's ability to divide and replicate. Hydroxyurea affects all cells, not just cancer cells, and its greatest effect is on rapidly dividing cells like blood cells and cells of the gastrointestinal tract. Stomatitis is inflammation and irritation of the mucous membranes in the mouth. The tissues become red and swollen, and ulcers form. This painful condition makes eating and drinking difficult.
Anemia
Extreme fatigue and shortness of breath characterize anemia. A low number of red blood cells decreases the amount of hemoglobin available to carry oxygen throughout the body. Muscles and organs cannot function properly without enough oxygen. Patients feel exhausted, air hungry, dizzy and weak. Oxygen therapy decreases symptoms, and in some cases, a blood transfusion is necessary.
Bruising and Bleeding
Another side effect of hydroxyurea in sickle cell anemia caused by bone marrow suppression is thrombocytopenia, or a low number of platelets. The body requires these special blood cells to form clots to stop bleeding. Sickle cell patients taking hydroxyurea bruise and bleed easily. Patients stop taking hydroxyurea when platelet counts fall below 100,000 per millimeter cubed because patients are at risk for hemorrhage, according to "Pearson Nurse's Drug Guide 2010."
Kidney Failure
When hydroxyurea works effectively, many blood cells die. Cell death creates toxic levels of certain waste products in the blood, like uric acid. High levels of uric acid cause nephropathy, or kidney damage. Without timely and appropriate medical care to reduce uric acid toxicity, permanent kidney damage can occur, resulting in kidney failure.
References
- National Heart, Lung and Blood Institute: Sickle Cell Anemia--Treatment
- "Pearson Nurse's Drug Guide 2010"; Wilson, B. A., Shannon, T. M., & Shields, K. M.; 2010
