Evaluation the effect of Donepezil on Cerebral Blood Flow Velocity in Alzheimer's Disease

The main cause of Alzheimer's disease (AD) is loss of cholinergic function. So, the choice strategy of therapy is to increase the level of acetylcholine (Ach) in the brain of by acetylcholinesterase inhibitors (AchEIs) such as Donepezil. This study evaluated the effect of donepezil on cerebral blood flow using non-invasive transcranial doppler (TCD) sonography. This clinical trial was performed on AD patients in two groups of case and control, each consisting of 11 patients. The case group who received donepezil medication was examined by TCD before (baseline), after four weeks of oral treatment with 5 mg/d donepezil and a further four weeks of 10 mg/d donepezil, administered orally. The control group did not receive any medications effective on AD and were examined by TCD only once. Peak systolic velocity (PSV), end-diastolic velocity (EDV) and mean flow velocity (MFV) velocities of posterior cerebral artery (PCA) and middle cerebral artery (MCA) were assessed and mini-mental state examination (MMSE) was carried out. There were not any significant difference between the case and control groups, in terms of age and sex. In the case group, mean MMSE score reached 20.2 ± 2.8 from a baseline value of 15.8 ± 3.3 after four weeks of oral treatment with 5 mg/d donepezil, and reached 20.6 ± 3.9 after four more weeks at 10 mg/d donepezil (P < 0.0001). In MCA, the difference in PSV and MFV values after four weeks of treatment at 10 mg/d donepezil was statistically significant, compared with the baseline values (P = 0.002 and 0.025, respectively). In PCA, the values of MFV and EDV after four weeks of treatment with 10 mg/d donepezil were statistically significant in comparison with the baseline value (P = 0.015 and 0.014, respectively). Donepezil, especially administered in doses of 10 mg/d, has an effect on increasing cerebral blood flow velocity and MMSE score in AD, but more extensive trials by other researchers are recommended.