Common Side Effects

• Approximately 36 percent of Arimidex users experience vasodilation or widening of the blood vessels making this the most common side effect of the drug, according to RxList.com. In some cases, vasodilation leads to a drop in blood pressure or fainting. Weakness, body pain and joint inflammation and pain are also common, occurring in at least 15 percent of users. More than 10 percent of women who take Arimidex experience back pain, headache, depression, nausea, inflammation of the throat and skin rashes. In addition, 11 percent of women who take Arimidex develop osteoporosis, a condition that makes your bones porous and brittle.
  
  

Other Side Effects

• Arimidex also has the potential to cause a number of other troublesome or annoying, but not dangerous, side effects. Some women experience gastrointestinal side effects from the drug, such as constipation, belching, dry mouth, abdominal pain, diarrhea and indigestion. Insomnia, dizziness, anxiety and tingling in the extremities are possible neurological and psychiatric side effects of the drug. Other side effects of Arimidex include sweating, coughing, hot flashes, shortness of breath, fever and an increased incident of upper respiratory and urinary tract infections.
  
  

Drug Interactions

• Some medications produce unwanted side effects when used in conjunction with Arimidex. For example, you should not take any estrogen supplements while using Arimidex as it will decrease the effectiveness of the drug reports RxList.com. In turn, you may need to take more Arimidex for it to work properly, increasing your risk of serious side effects. In addition, doctors do not prescribe the breast cancer drug Tamoxifen for patients also taking Arimidex due to the likelihood of increased side effects from both drugs.
  
  

Risks

• In addition to minor side effects and the risk of interactions, Arimidex has the potential to cause serious medical complications. In 17 percent of patients with pre-existing cardiovascular conditions, Arimidex causes stroke, reports RxList.com. A loss of bone density and an increased risk for bone fractures is another potential risk, especially when used for 12 months or more. In some women, Arimidex causes an increase in LDL cholesterol levels, which can contribute to heart attack or cardiovascular disease, according to the Mayo Clinic. Use of the drug can also cause impairment of the liver or kidneys.
  
  

Considerations

• Because it lowers estrogen levels, doctors rarely prescribe Arimidex for women who have not experienced menopause. The drug also can cause fetal death and is likewise not prescribed for use in pregnant women. Before prescribing the drug for you, your doctor may perform a pregnancy test to be safe. Because of its side effects, your doctor is not likely to prescribe Arimidex for you if you have a history of stroke or disease of the heart, kidneys or liver.