Cytopenia Causes and Risk Factors
Chemotherapy and radiation therapy both reduce the number of blood-forming stem cells in cancer patients, but chemotherapeutic agents have a greater adverse effect because they suppress bone marrow function in several ways. The degree of damage is related to the particular drug(s) and the dose.
Chemotherapeutic agents can produce deficiencies in all blood cell types by
- damaging blood-forming stem cells,
- suppressing the kidneys' production of erythropoietin (hormone that stimulates blood cell production), and
- triggering red cell destruction (hemolysis) by inducing an immune response that causes the body to mistakenly identify erythrocytes as foreign bodies and destroy them.
Malignant tumors can cause anemia and other cytopenias when they directly invade bone marrow and suppress marrow function. Malignant cells also can migrate from tumors in other parts of the body to bone marrow. Tumors also can replace normal blood-forming stem cells with abnormal clones.
Medications used to treat bacterial infection and other illnesses also can contribute to immune system suppression. Some of these are listed here:
- Antacids: cimetidine (Tagamet)
- Antibiotics: chloramphenical (Chloromycetin), sulfonamide (Thiosulfil, Gantanol); cephalosporin (Cephalaxin), vancomycin (Vancocin)
- Anticonvulsants: phenytoin/hydantoin (Dilantin), felbamate (Felbatol), carbamazepine (Tegretol)
- Antimalarials: chloroquine (Aralin)
- Antivirals: ganciclovir (Vitrasert), zidovudine (AZT)
- Cardiac drugs: diltiazem (Cardizem), nifedipine (Procardia), verapamil (Calan)
- Diabetes drugs: glipizide (Glucotrol), glyburide (Micronase)
- Hyperthyroid drug: propylthiouracil
- NSAIDs (nonsteroidal anti-inflammatory drugs): phenylbutazone (Butazolidine), indomethacin (Indocin, Indochron E-R)Due to potentially severe gastrointestinal and cardiovascular side effects, NSAIDs should only be used as instructed.
- Rheumatoid arthritis drugs: auranofin (Ridaura), aurothioglucose (Solganal), gold sodium thiomalate (Myochrisine)