Nearly a fifth of people taking Cipro, the anti-anthrax drug, have developed side effects, according to a study of 490 patients in Boca Raton, Fla., where a tabloid editor died of anthrax last month.
Some experts say the study has worrisome implications because at least 32,000 people have been prescribed Cipro and other antibiotics after possible anthrax exposure. Many others have asked their physicians for a personal stash.
The side effects, which were not lethal and almost never led to hospitalization, included breathing problems, itching and swelling of the face, neck and throat. One expert suggested anxiety may have produced some of the symptoms.
The findings will be published in today's issue of the Morbidity and Mortality Weekly Report from the national Centers for Disease Control and Prevention.
"We've had no surprises," said Dr. Julie Gerberding, acting deputy director of the CDC's National Center for Infectious Diseases. "The adverse events that people are reporting in Florida are no different than what we've typically seen" with Cipro and doxycycline.
Cipro is a member of the antibiotic class known as fluoroquinolones, considered a last line of defense against some bacterial infections. The drugs' most common side effects include nausea, diarrhea, vomiting, abdominal pain or discomfort, headache, rash and restlessness.
Doxycycline, another antibiotic approved to treat anthrax, generally has similar but fewer side effects.
The 32,000 people taking antibiotics, including 16,000 postal workers, may have been exposed to anthrax in Florida, New Jersey, New York and Washington, D.C. The numbers do not include patients elsewhere who have received prescriptions from their personal doctor to keep in their medicine cabinet "just in case."
About 5,000 people still believed to be at risk for developing an inhaled anthrax infection are being told to take a 60-day regimen of antibiotics.
As demand for Cipro skyrocketed in the general population, researchers have been warning about antibiotics' side effects. Indiscriminate use of antibiotics, they add, can lead to the growth of bacteria in the body that are resistant to drugs.
The side effects among people treated appropriately "should bring a message to those of you who are thinking of taking it that you are risking a personal problem," said Dr. Stuart Levy, president of the Alliance for the Prudent Use of Antibiotics. "Here's the first blush out of this experiment."
A study in the December issue of the Annals of Pharmacotherapy details 45 cases of severe side effects--including tingling, numbness, burning pain, twitching and spasms--associated with fluoroquinolones. The drugs are also not recommended for children, because they stunt bone growth, and pregnant women.
Media Company Employees Treated
Boca Raton is home to American Media Inc., which publishes the Sun and the National Enquirer. Sun photo editor Bob Stevens died of inhaled anthrax Oct. 5, the first casualty of the bioterrorism attacks. From Oct. 8 to 10, 1,132 AMI employees received precautionary antibiotics; 970 of them got Cipro.
Of 1,000 employees tracked after 14 days, 80% said they had continued to take the antibiotics.
The survey of 490 AMI workers in Boca Raton focused on physical side effects, but those symptoms could be the result of anthrax anxiety, said Dr. William J. Hall, president of the American College of Physicians and the American Society of Internal Medicine.
"Any time you influence people's thinking about their health in this way, there are going to be a number of medical complaints that may or may not be related to the drug itself," Hall said. "This is just normal human behavior."
A 60-day supply of antibiotics should kill all bacteria in a person's body--the good with the bad. As a result, diarrhea and abdominal pain can be expected. "It's not a question of if, but when, people are going to get side effects from a broad-spectrum antibiotic [such as Cipro]. It's not necessarily a side effect; it's an expected effect."
Gerberding played down criticism that too many people have been prescribed antibiotics. "When we have the immediate event where there's a case of anthrax, or a powdered envelope that proves to be anthrax, we cannot immediately ascertain who's at risk for exposure," she said.
As more information emerges, Gerberding added, "it's possible to narrow the circle of people who require treatment and stop antibiotics in all those who were unnecessarily started."
Hall said more studies are needed to observe how patients react to 60 days of antibiotics. "We need to really understand what's the implication of putting thousands of people on an antibiotic for two months. There's never been an experience like this in the world. We have no idea what to expect from this."