Dramatic improvement in Down syndrome-associated cognitive impairment with donepezil.

OBJECTIVE: To report 2 cases of patients with Down syndrome and severe cognitive impairment who gained dramatic improvements in quality of life (QOL) upon donepezil treatment. CASE SUMMARIES: Case 1. A 38-year-old woman with Down syndrome, diagnosed with secondary progressive dementia when her mental state had deteriorated rapidly after graduation from junior high school, started donepezil treatment. The loading dose was 3 mg/day and was increased to 5 mg/day for maintenance. One month after the dose was increased, adverse effects such as soft stool and urinary incontinence appeared. These adverse effects disappeared when the dose was decreased again to 3 mg/day. Her QOL improved dramatically with this minimal dose. She recovered verbal and written communication skills that she had lost for the past 21 years. Case 2. A 22-year-old man with Down syndrome, who had been diagnosed as having severe mental retardation, was put on donepezil therapy. Both loading and maintenance doses were 3 mg/day. His QOL had also dramatically improved, with some recovery in verbal communication. Transient agitation/violence and transient muscle weakness appeared during the first few months of treatment. DISCUSSION: Patients with Down syndrome may be more sensitive to donepezil therapy than others and may benefit from this medicine, although they may also have adverse effects more frequently.
CONCLUSIONS: Donepezil may be a useful medicine for some patients with Down syndrome with severe cognitive impairment or mental retardation if the adverse effects are manageable.