ROCHESTER, Minn., July 19 (UPI) -- U.S. researchers have found that an Alzheimer's treatment drug temporarily slows the onset of the disease in patients with mild cognitive impairment.
The drug donepezil seems to slow the progression of mild cognitive impairment into Alzheimer's for a short period of time, whereas vitamin E -- shown to delay the disease's progression -- had no effect on inhibiting its onset, Mayo Clinic researchers found.
The research showed patients taking donepezil had a reduced risk of progressing to Alzheimer's disease compared to patients who took vitamin E or a placebo.
However, after 18 months, the drug's effects wore off and patients were at the same risk as other treatment groups.
Researchers did not know why donepezil loses its protectivity over time, but suggest the disease's process may outweigh the chemical effect.
About 10 to 15 percent of patients with mild cognitive impairment progress to Alzheimer's each year, but the progression does not occur in all patients.
