CDC Considers Doxycycline Over Cipro

Centers for Disease Control officials said Monday they are moving away from favoring ciprofloxacin, or Cipro, as the only first-line treatment for anthrax infection. Officials will now recommend the older and cheaper, yet equally effective antibiotic doxycycline.

"We consider doxycycline as a better choice in the current situation where we have tens of thousands of people on that drug," Centers for Disease Control anthrax expert Dr. Bradley Perkins told Reuters.

Currently, the FDA has approved three antibiotics for the treatment of anthrax disease: penicillin, doxycycline and Cipro. Yet the recent purchasing frenzy has favored only Cipro, forcing its maker, Bayer AG, to triple production in the next three months to meet increased demand.

Preventing Resistance

Such a large increase of antibiotics in the hands of the public, as well as the recent decision to treat thousands of high-risk individuals who have been exposed to anthrax spores in New Jersey and Washington, D.C. have raised concerns about antibiotic resistance.

"For that reason we are moving more strongly to the use of doxycycline in this particular situation where we know that the strains that we have been dealing with are as susceptible to doxycycline," Perkins said.

The recent move by the government to de-emphasize the reliance on Cipro appears to fall in line with comments made by the CDC last week.

"I think it would certainly be healthier from a broad community sensitivity to antibiotics perspective to have some better balance of folks on different antibiotics," said Dr. Jeffrey Koplan, director of the CDC, in a telephone briefing on Friday. "It would be healthier overall and would certainly be perfectly healthy for the individuals who are taking prophylaxis."

Resistance to Cipro concerns many experts as it is a newer antibiotic belonging to a class of drugs widely relied upon to treat a range of infections. Reducing the use of Cipro now will make the drug more effective for treating other bacterial diseases in the future.

Why Favor Cipro?

Most naturally occurring strains of anthrax are sensitive to all three antibiotics, however, anthrax experts have previously reported the existence of engineered anthrax strains resistant to doxycycline and penicillin.

There are no such reports about resistance to Cipro. Therefore only resistance to penicillin and doxycycline is automatically assumed in biological attacks before the sensitivity of the strain can be determined.

However, the CDC has conducted sensitivity testing of the anthrax bacteria at the center of recent cases and recommends that Cipro or doxycycline be used as first-line agents for post exposure prevention of inhalation anthrax. High-dose penicillin may also be an option, depending on a patient's ability to tolerate each drug.

So, right now there is no special reason to prefer Cipro. "Yes, it is one of the drugs we recommend and we recommend in the exact same breath doxycycline, which would be just as good," Koplan said.

Yet, according to Perkins, in a situation where new anthrax infections from new sources are suspected, doxycycline and penicillin resistance would again be assumed until sensitivity tests demonstrate otherwise.