Tariot et al.P^' conducted a randomized, double- blind, placebo-controlled clinical trial of mem- antine for 24 weeks in 404 outpatients from 37 US centres who had moderate to severe AD and who were already taking donepezil; 322 patients completed the trial. Patients were selected accord- ing to the National Institute of Neurological and Communicative Disorders and Stroke-Alzheimer Disease and Related Disorders Association (NINCDS-ADRDA) criteria for AD