[Tacrine: progress in treatment of Alzheimer's disease?].

The cholinesterase inhibitor tacrine exerts a marked therapeutic effect only at a dose which is not tolerated by many patients because of the gastrointestinal side effects and hepatotoxicity of the drug. In patients who tolerate a high dose of tacrine the mean increase in cognitive abilities is roughly equivalent to the decline which occurs within 1 year in an untreated group. At a high dose tacrine may also temporarily delay the progression of symptoms of Alzheimer's disease. Only a minority of patients with mild to moderate Alzheimer's disease can be treated with tacrine. For them, however, tacrine is the most promising treatment option presently available.