The U.S. Centers for Disease Control and Prevention (CDC) announced Tuesday that a large number of people prescribed antibiotics during last year's anthrax scare reported numerous adverse side effects or discontinued treatment before their 60-day course was finished. Last fall, physicians prescribed nearly 10,000 postal, media and Senate office workers two antibiotics, doxycycline and ciprofloxacin, after five people died and 13 others became ill from anthrax inhalation.

According to the CDC, of the 6,200 employees interviewed by the government, 3,032 people complained of side effects ranging from nausea to headaches and dizziness. Only 2,700 people finished their treatment. Health officials are calling the numbers surprising, as the medications typically show fewer side effects in users.