With the heightened concern for the spread of the anthrax disease, doctors and researchers have been developing new antibiotics to treat it. Ciprofloxacin -- commonly known as Cipro -- has been the most popular, but recently doxycycline and amoxicillin have become widely used as well.

These drugs are prescribed for people who have been exposed to anthrax. Many people who have not been exposed, however, are using them as a preventive measure.

Because these drugs needed to be available so quickly, some speculation about whether they might not be completely effective remains.

"There have been reports of engineered strains of anthrax that are resistant to amoxicillin and doxycycline," said Dr. Bruce Jansen, a University Health Services physician. "But all of the anthrax cultured so far from the bioterrorism incidents have been sensitive to all three antibiotics."

According to the Centers for Disease Control and Prevention Web site, there is no evidence that Cipro is more effective than doxycycline. But to preserve the effectiveness of Cipro in helping infected people, doxycycline is now more commonly prescribed for prevention.

"The dose of Cipro for post-anthrax exposure is 500 milligrams twice a day, which is a medium range for this medication," Jansen said. "At this time, no asymptomatic person will be treated with medication unless there is documented, definite exposure to anthrax."

Some people who have not yet been exposed but are in "hot spots" for anthrax have begun to take to antibiotics, though. Several of Penn State's interns in Washington, D.C., said they have taken Cipro.

Jansen said a person must have a positive test or culture of the suspected material to be given Cipro in most areas of the nation.

Some students have said that they would take a preventive anthrax antibiotic if it became available to everyone.

"I would take it," said Michele Pendrak (sophomore-premedicine). "To me, it would probably be just like getting a flu shot."

Right now, however, most Americans cannot get access to the antibiotics. But if people suspect anthrax exposure, they must seek immediate help.

"Students who think they have come in contact with a substance containing anthrax need to immediately and safely contain the suspected substance, change and bag their clothes, and contact the police, public health department or UHS with their report," Jansen said.

UHS will give out the antibiotics only to people who have tested positive to anthrax exposure.