Cognitive relapse after discontinuation of drug therapy in Alzheimer's disease: cholinesterase inhibitors versus nootropics

In a cross-sectional study of outpatients diagnosed with dementia of the Al zheimer type who had been treated with a broad variety of drugs supposed to improve cognition or to delay cognitive decline, we have investigated the effects of abruptly discontinuing therapy on cognition. Termination of ther apy with any cholinesterase inhibitor was associated with a cognitive decli ne during the following 6-7 weeks which was significantly more pronounced t han that experienced by patients who had received nootropic drugs or calciu m channel blockers (3.41 vs. 1.17 points on the ADAS-Cog scale; -1.14 vs. - 0.06 points on the MMSE scale). This effect was not modified by gender, apo lipoprotein E genotype, or the extent of ventricular enlargement on CT scan s. Its magnitude was comparable to the cognitive response observed in publi shed clinical trials when cholinesterase therapy commenced, and also with t he data obtained during a 6-week placebo washout phase.