Tacrine in the treatment of Alzheimer's disease. A clinical update and recent pharmacologic studies.

The initial report of the effectiveness of tacrine or tetrahydroaminoacridine (THA) in the treatment of some patients with Alzheimer's disease has been confirmed by further study of additional subjects and by preliminary reports from other investigators. The major side effect, elevation of liver enzymes, is shown to be reversible, dose-dependent and without significant hepatic pathology. Therapeutic serum concentrations of THA vary between 7 and 20 ng/ml. In addition to its presumed action as an acetylcholinesterase inhibitor, data are presented demonstrating marked effects on other brain neurotransmitters in animal models.