The authors reviewed historical data in the development of THA, as wel
l as recent data on its pharmacological properties and therapeutic eff
ects on cognitive dysfunction. A medline search was conducted to ident
ify the trials conducted with THA in Alzheimer's disease (AD) patients
. The findings seem to lend support to some palliative action of THA,
especially at higher doses, but in these doses about 2/3 of the patien
ts experience significant adverse reactions. The significance of these
findings is discussed, with emphasis on the their relevance for the m
anagement of AD patients.