Leukemia is a cancer of the white blood cells. One abnormal cell reproduces in the bone marrow without abiding by any regulations or controls. This results in a high number of abnormal clones. The abnormal white blood cells take over, crowd out the other blood cells in the bone marrow and do not allow them to develop. There are several types of leukemia. Acute promyelocytic leukemia is one of these types.
Tretinoin
Tretinoin is also referred to as all-trans retinoic acid, or ATRA. The white blood cells in acute promyelocytic leukemia are immature cells, called promyelocytes. Normally, promyelocytes develop into neutrophils, eosinophils or basophils, but the abnormal promyelocytes in this leukemia stay immature. Tretinoin makes the promyelocytes mature, according to "Harrison's Principles of Internal Medicine." This treatment can cause a side effect called retinoic acid syndrome. The syndrome can occur in the first three weeks that people start taking the medication. It develops if cancer cells attach to the lining of the blood vessels in the lungs. The symptoms include chest pain, difficulty breathing and fever.
Arsenic Trioxide
Arsenic trioxide is a heavy metal poison that is also an effective treatment for acute promyelocytic leukemia for those people who do not respond to tretinoin. More than 85 percent of these patients improve when they take arsenic trioxide, as explained in "Goodman & Gilman's The Pharmacological Basis of Therapeutics." Some people who take arsenic trioxide may have side effects similar to retinoic acid syndrome. Others need to be monitored for any heart abnormalities. There are currently several clinical trials underway that are investigating whether arsenic trioxide can be the first treatment for this type of leukemia or if it should be prescribed along with tretinoin. The Memorial Sloan-Kettering Cancer Center is one institution conducting these studies.
Cytarabine and Daunorubicin
Cytarabine and daunorubicin treat several types of leukemia. Once cytarabine is inside of a cell, it changes to an active form and interferes with the DNA of that cell. Daunorubicin interferes with the DNA and RNA of a cell. "Harrison's Principles of Internal Medicine," states that approximately 10 percent of people who used these medications for acute promyelocytic leukemia died from disseminated intravascular coagulation, or DIC. This is a disorder in which clots form throughout the blood vessels. When platelets and clotting proteins are used up, hemorrhaging occurs.
References
- "Goodman & Gilman's The Pharmacological Basis of Therapeutics"; Laurence Brunton, Ph.D.; 2006
- "Harrison's Principles of Internal Medicine"; Anthony Fauci, M.D., Dennis Kasper, M.D., Dan Longo, M.D. et al.; 2008
- National Institutes of Health: Tretinoin and Arsenic Trioxide
