Chemotherapy drug treatments can cause anemia, a condition that results in a low red blood cell count (RBCs). Symptoms such as fatigue, weakness, increased heart rate, dizziness and shortness of breath result because there aren’t enough red blood cells to carry nutrients and oxygen to the body tissues. These symptoms can also inhibit the intensity of the cancer treatment.  
Most patients treated with chemotherapy drugs are likely to get anemia. Patients with lymphoma, myeloma and leukemia are also susceptible to anemia because these diseases grow within the bone marrow and squeeze out more healthy red blood cells. Some patients may not get anemia because of cancer, but some may already have a tendency toward it such as premenopausal women.  
A doctor can determine whether or not a patient has anemia by evaluating the concentration of hemoglobin in the blood and the hematocrit levels. 
– Red blood cells contain a protein called hemoglobin that carries oxygen to the muscles and organs.  If the number of RBCs is low, the hemoglobin concentration is below the normal range. 

The normal range for women is 12 to 16 grams per deciliter and 14 to 18 grams per deciliter for men. 
– The percentage of total blood volume occupied by RBCs is known as hematocrit. The normal hematocrit levels should be between 37% and 52%. Usually, these percentages are higher in men than in women. 
Normal Adult Values-Male             Female 

RBC                          4.5 – 6.0 M/ul4.2 – 5.4 M/ul 

Hemoglobin (HgB)14 – 18 g/dL12 – 16 g/dL 

Hematocrit (Hct)40 – 52%37 – 47% 

Drugs That Cause Anemia 
Overall, most chemotherapy drugs can cause anemia because they tend to lower blood cell counts due to their toxic effects on bone marrow that is responsible for producing blood cells.  
Some cancers cause anemia due to blood loss. Cancers that have an impact on the genitourinary or gastrointestinal tracts may cause bleeding. Tumors are another cause of bleeding, they can bleed from within.  

Treatments to Reduce Anemia 
If a cancer patient shows signs of severe anemia, a blood transfusion can be given to return the RBC levels to a proper level. This option is normally only used in very severe cases because blood transfusions may present some risks. 
A more common approach taken to maintain the proper RBC levels is to use a drug called Procrit or Epogen (epoetin alfa). This substance acts like the body’s naturally-occurring substance, erythropoietin, by stimulating red blood cell production. Epogen is usually administered once a week by an injection to boost the hemoglobin levels.  
A more recent drug used to treat chemotherapy-induced anemia is Aranesp (darbepoetin alpha), approved for use in 2002, it has the same characteristics as the naturally-occurring erythropoietin.