A drug once approved as an antihistamine in Russia improved thinking processes and ability to function in patients with Alzheimer's disease in a study conducted there, said an expert at Baylor College of Medicine in Houston. The findings are published in the current issue of the journal The Lancet.

"More research is needed, but we are encouraged by the effect the drug Dimebon had on Alzheimer's patients" said Dr. Rachelle Doody, professor of neurology at BCM and lead author of the study.

In the study, the authors noted that Dimebon is the first drug for Alzheimer's disease that demonstrated continued improvement in patients over a 12 month period. Other approved drugs do not have this effect.

Half of the 183 patients in the Russian study received Dimebon; the other half were given a placebo or an inactive pill. Clinicians at the study sites then monitored the patients' progress over the next year on five different outcomes. All of those in the study had mild to moderate Alzheimer's disease.

"What we saw in the clinical trial is that people on the medication continued to improve over time," Doody said. "Those on placebo continued to decline."

Researchers believe the medication works by stabilizing mitochondria, the cellular components that produce energy, and possibly by inhibiting brain cell death. Researchers evaluated patients' thinking and memory ability, overall function, psychiatric and behavioral symptoms, and ability to perform daily activities.

"Usually at this point in a drug's development, we are happy to see improvement in one of the outcome measures," Doody said. "We saw improvement in all five."

Some participants complained of occasional dry mouth, but no one opted out of the study because of the side effects.

"As we continue research, we hope to replicate these results," Doody said. "My belief is that this drug will turn out to be useful for Alzheimer's disease, regardless of the stage of the disease."

Doody said this is only the first study looking into the effects of Dimebon on Alzheimer's disease. She also noted that it involved only a relatively small population from one specific region of the world. The ongoing Phase 3 study will include several international locations including the United States.