Management of cognition and function: new results from the clinical trials programme of Aricept(R) (donepezil HCl)

Ideally, treatment for Alzheimer's disease (AD) should prevent or cure the disease. Unfortunately, these goals appear unobtainable in the foreseeable future. Nevertheless, symptomatic relief is a feasible treatment option for AD patients and is available currently in the form of cholinesterase inhibitors such as tacrine, donepezil, metrifonate and rivastigmine. Donepezil is a second-generation, piperidine-class, selective and reversible acetylcholinesterase inhibitor. Four double-blind, placebo-controlled clinical trials of donepezil, involving over 1900 individuals with mild to moderate AD, have been published recently. In all trials, significant improvements in cognition were observed consistently for both therapeutic doses of donepezil (5 and 10 mg/d), relative to placebo. Similar donepezil-associated benefits were reported for global functioning. In addition, in one 24-wk, multinational clinical trial, patients receiving donepezil (10 mg/d) performed better than placebo-treated patients in their ability to perform complex daily functioning tasks. Donepezil was well tolerated in all trials, with approx. 79% of all donepezil-treated patients completing the studies compared with approx. 84% of placebo-treated patients. The most common adverse events associated with donepezil were generally cholinergic-induced and gastrointestinal in nature (e.g. nausea, diarrhoea, and vomiting) which were generally mild, transient and tended to occur after the dose was increased to 10 mg/d from 5 mg/d after 1 wk only. Sleep disturbances also occurred as the clinical trials utilized a bedtime dosing regimen. There was no evidence of organ toxicity or clinically significant treatment-emergent laboratory test abnormalities. Thus, donepezil appears to be a beneficial symptomatic treatment for patients with mild to moderate AD.