Study: Antibiotics May Hold Promise in Slowing Alzheimer's

Two antibiotics, doxycycline and rifampin, may hold promise in slowing the progression of Alzheimer's disease, according to a study presented October 9 by Canadian researchers at the annual meeting of the Infectious Diseases Society of America in San Diego.

Both drugs are used to treat bacterial infections. Rifampin is most commonly used to treat tuberculosis, while doxycycline is most commonly used to treat pneumonia, lyme disease, acne, venereal diseases, anthrax and to prevent malaria

The study involved 101 people with suspected mild to moderate Alzheimer's disease and was conducted at five clinics throughout Canada. Fifty patients received placebo pills, while 51 participants received 200 mg of doxycycline and 300 mg of rifampin daily for three months.

The participants were tested to determine their mental function before the study began and six months later. On a 70-point scale, the mental function scores of those taking antibiotics declined by an average of 2.75 points less over six months than those who received the placebo. At 12 months, there was still a difference between the two groups, although it was not considered statistically significant.

According to the researchers, adverse effects, including nausea, diarrhea and sleep disturbances, were relatively minor with no significant difference in incidence between the two groups.

Previous research has suggested that the bacterium Chlamydia pneumoniae may play a role in causing Alzheimer's disease. The two antibiotics examined in this study are considered very effective against this germ.

The researchers said antibiotics may either interfere with the accumulation of amyloid plaques around the neurons in the brain or provide relief through their anti-inflammatory effects.

Due to the small size of the study, the Alzheimer's Association expressed caution about the new research finding, noting that it cannot now recommend such treatments. William Thies, a vice president at the association, said it would like to see a large, well-controlled clinical trial before making any recommendation one way or the other about the potential of these two antibiotics as treatments for Alzheimer's disease.

Other sources: Alzheimer's Association