What are hematopoietic drugs?
Hematopoietic medications increase the production of erythrocytes or red blood cells, leukocytes or white blood cells, and platelets, which are small clot forming fragments of a larger cell called a megakaryocyte.
Let’s first understand haematopoiesis!!
Haematopoiesis means”blood” “to make” or to make blood in body
Hemopoiesis is the formation of blood stem cells.
Classification of Hematopoietic Drugs
Minerals
- Ferrous sulfate.
- Iron dextran
Vitamins
- Folic acid
- Cyanocobalamin (vitamin B12)
- Hydroxocobalamin (vitamin B12, CYANOKIT)
Hematopoietic Growth Factors
- Epoetin alfa (EPOGEN, PROCRIT)
- Epoetin beta (MIRCERA)
- Darbepoetin alfa (ARANESP)
- Filgrastim (NEUPOGEN)
- Pegfilgrastim (NEULASTA)
- Sargramostim (LEUKINE)
Overview of haempoetics
Mature blood cells are continuously formed in the bone marrow and are removed from the circulation by reticuloendothelial cells in the liver and spleen.
The process by which blood cells are replaced is called hematopoiesis.
This process requires minerals and vitamins and is regulated by hematopoietic growth factors that promote the differentiation and maturation of marrow stem cells to form leukocytes, erythrocytes, and platelets.
Anemia
It is a subnormal concentration of erythrocytes or hemoglobin in the blood, can result from inadequate erythropoiesis, blood loss, or accelerated hemolysis.
Erythropoiesis can be impaired by a lack of essential nutrients or by the myelosuppressive effects of certain drugs or irradiation.
Infection, cancer, endocrine deficiencies, and chronic inflammation can also cause anemia. Iron, folic acid, and vitamin B12 deficiencies are the most common causes of nutritional anemia.
Here we are talking about the uses of minerals, vitamins, and hematopoietic growth factors in the treatment of anemia and other blood cell deficiencies.
Drugs in detail
Minerals
Iron, an essential dietary mineral, serves as an important component of hemoglobin, myoglobin, and a number of enzymes.
The average dietary intake of iron is 18 to 20 mg/day, but people with normal iron stores absorb only about 10% of this amount.
The absorption of iron is regulated by the amount of iron that is stored in the intestinal mucosa.
Iron is absorbed from the intestines into the circulation, where it is bound to transferrin and transported to various tissues, including the bone marrow and liver.
In these tissues, iron is stored as ferritin . In the marrow, iron is incorporated into heme and packaged in new erythrocytes. The erythrocytes circulate in the blood for about 120 days and then are taken up and degraded by reticuloendothelial cells. These cells later return most of the iron to the plasma so that it can be used again in erythropoiesis.
Iron is highly conserved by the body, and only small amounts of it are excreted via the intestinal tract.
Oral Iron Preparations
Iron is administered orally in the form of ferrous salts, including ferrous sulfate, ferrous gluconate, and ferrous fumarate.
Iron contained in these preparations is absorbed in the same manner as is dietary iron.
In patients with iron deficiency, the amount of iron absorbed increases progressively with larger doses, but the percentage absorbed decreases as the dosage increases.
In iron deficiency states, oral iron preparations are usually administered three times a day in doses that provide a total of 100 to 200 mg of elemental iron daily.
The various iron salts contain different percentages of elemental iron.
Ferrous sulfate contains about 20%, so that a 300-mg tablet contains approximately 60 mg of elemental iron.
The duration of iron therapy depends on the cause and severity of the iron deficiency. In general, a course of about 4 to 6 months of oral iron therapy is required to reverse uncomplicated iron deficiency anemia.
Parenteral Iron Preparations
Iron preparations for parenteral therapy include iron dextran, iron sucrose, and sodium ferric gluconate.
Iron dextran is a mixture of ferric hydroxide and dextran. Both low-molecular-weight and high-molecular-weight iron dextran preparations have been used, but the low-molecular weight preparations cause fewer adverse effects. Iron dextran is intended for intramuscular or intravenous treatment of iron deficiency anemia in patients who cannot tolerate oral iron preparations or fail to respond to oral iron therapy.
After administration, the iron dextran complex is removed from the circulation by the reticuloendothelial system, and the iron is transferred to the plasma for distribution to the bone marrow and other tissues.
The dosage required for each patient is calculated on the basis of the observed hemoglobin concentration and body weight.
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