What are the risk factors for aplastic anemia?

A risk factor is anything that changes your chance of getting a disease. For example, certain cancers have different risk factors. Exposing skin to strong sunlight is a risk factor for skin cancer. Smoking is a risk factor for many cancers. But risk factors don’t tell us everything. Having a risk factor, or even several, does not mean that you will get the disease. And not having a risk factor doesn’t mean that you won’t get the disease.

We know that certain aplastic anemias are inherited. Having Fanconi anemia or dyskeratosis congenita increases the risk of developing aplastic anemia.

Exposure to certain drugs and chemicals may increase the risk of acquired aplastic anemia. It’s important to realize that these medications are safe for most of the people who take them. In some cases, however, people develop aplastic anemia after receiving one of these drugs. Likewise, some viruses are linked to acquired aplastic anemia, but aplastic anemia develops only in a very small percentage of people with these infections.

Medicines

Some of the medicines linked to aplastic anemia include:

• Nonsteroidal anti-inflammatory drugs (NSAIDs) -- medicines used to treat pain and inflammation. Examples include indomethacin (Indocin^®), piroxicam (Feldene^®), and diclofenac (Voltaren^®)
• Amphetamines, including MDMA (Ectasy)
• Antibiotics, including sulfonamides (“sulfa drugs”) and forms of penicillin
• Anti-thyroid drugs, such as propylthiouracil and methimazole (Tapazole^®)
• Carbonic anhydrase inhibitors, including acetazolamide and methazolamide (these are used to treat glaucoma)
• Diabetes medications, including tolbutamide, carbutamide, and chlorpropamide
• Diuretics (water pills), such as furosemide (Lasix^®) and thiazides
• Drugs used against malaria, including quinacrine and chloroquine
• Phenothiazines (Thorazine^®, Compazine^®) -- medicines used for nausea and certain psychiatric problems
• Allopurinol (Zyloprim^®) -- used for treating gout
• Ticlopidine -- used to prevent strokes and heart attacks
• Anti-seizure drugs like carbemazepine (Tegretol^®), phenytoin (Dilantin^®), and valproic acid
• Chloramphenicol, an antibiotic (no longer available in the United States)
• Mesalazine which is used to treat ulcerative colitis and Crohns disease

This is only a partial list of the drugs most often associated with aplastic anemia. Other drugs may also cause this disease. The best way to avoid aplastic anemia from drugs is to take medicines only if they are necessary.

Chemicals

Exposure to chemicals such as solvents and pesticides at home or in the workplace is also a risk factor. These include:

• Benzene, which is found in gasoline, automobile exhaust fumes, cigarette smoke, emissions from coke ovens and other industrial processes, and waste water from certain industries, is the most common offender.
• Industrial pesticides, like organophosphates and carbamates

Other risk factors

Other conditions have been linked to aplastic anemia, such as:

• Hepatitis
• Viruses such as Epstein-Barr virus, cytomegalovirus (CMV), parvovirus B19, and HIV.
• Pregnancy
• Auto-immune diseases like lupus (systemic lupus erythematosus) and rheumatoid arthritis
• Severe radiation poisoning (as seen after an atomic bomb explosion)