Antibiotic use may help slow Alzheimer's

Experts find early results exciting and hope promising benefits from this novel treatment can be replicated in larger trials.

By Victoria Stagg Elliott, AMNews staff. Oct. 27, 2003.

The mental decline caused by Alzheimer's disease may be slowed by daily doses of two antibiotics, according to a study presented at the recent Infectious Diseases Society of America annual meeting in San Diego.

In a randomized study, researchers at McMaster University in Hamilton, Ontario, administered either 200 mg of doxycycline with 300 mg of rifampin, or a placebo for three months to 101 patients with mild to moderate Alzheimer's who were not responding to traditional drug regimens.

Patients were assessed at six and 12 months. At both points, the patients who had received the antibiotics showed less of a decline. However, because of patient dropout, the results were not statistically significant at 12 months.

"Does this mean you should ask that mom or dad be put on an antibiotic regimen if they have Alzheimer's?" said Mark B. Loeb, MD, the study's lead author and associate professor at McMaster. "If everything else has failed, it's a possibility and something to talk to the physician about."

Experts are excited about the possibility of a new therapy for a disease that has so few treatment options, especially with drugs that have such significant track records. Both rifampin and doxycycline are old drugs that most physicians have few reservations about using, even over the long term. These antibiotics are also less expensive than the currently available Alzheimer's drugs.

"If it works -- and this report sounds encouraging but not yet definitive, there is more testing to go -- then the cost benefit would be excellent," said Ashley Bush, MD, PhD, associate professor of psychiatry at Massachusetts General Hospital in Boston.