Clinical studies of the cholinergic deficit in Alzheimer's disease. II. Psychopharmacologic studies.

Two studies investigated the ability of physostigmine, given both intravenously and orally, to reduce symptoms of Alzheimer's disease. Intravenous physostigmine significantly and reliably enhanced memory in 13 of 16 patients tested, but the dose producing the improvement varied among patients. Oral physostigmine decreased overall symptom severity in a reliable way in seven of 12 patients tested. The extent of improvement was correlated with the increase in mean cortisol secretion produced by physostigmine, suggesting that the drug improved behavior and cognition only to the extent that it had a specific central cholinomimetic effect. There was no significant association between response to physostigmine and results of a dexamethasone suppression test and physostigmine had no effect on growth hormone secretion.