Anticholinergic drugs impair one's ability to learn new material, even
at routine clinically used doses. During the trihexyphenidyl phase of this
double-blind crossover trial, elderly normal subjects complained of
confusion and memory impairment and demonstrated a pattern of deficits in
memory function compatible with that previously reported to result from
anticholinergic drugs. The subjects neither complained of nor demonstrated
memory impairment while taking amantadine, which is believed to exert its
pharmacological effects upon extrapyramidal disorders via dopaminergic
mechanisms and does not appear to be associated with memory impairment.
Anticholinergic drugs should be avoided whenever possible in the elderly
and especially in those suffering dementia.