Alzheimer's disease (AD) is a major neuropsychiatric disorder affecting more 
than 5 million Americans over age 65. By the year 2050, AD is expected to affect 
over 30 million. Characterized by neuronal cell death accompanied by the 
accumulation of neurofibrillary tangles and neuritic plaques, AD results in 
devastating clinical symptomatology with a lasting psychosocial and financial 
impact. Studies have shown that the current treatments for AD, cholinesterase 
inhibitors (ChEI's) and NMDA receptor antagonists, have limited efficacy. The 
5-HT-6 receptor antagonists Idalopirdine and Intepirdine have shown the most 
progress in current clinical trials and warrant consideration as emerging 
treatments for AD. Areas covered: This review discusses 5-HT6 antagonists 
currently in clinical trials as potential treatments for AD symptomatology and 
how 5-HT6 physiology may play a positive role in alleviating AD symptom 
pathophysiology. A literature search using PubMed was conducted using the terms 
Idalopirdine, Intepirdine, 5-HT-6 antagonist, and AD as keywords. 
Clinicaltrials.gov and Alzforum were also used to obtain information on clinical 
trials. Expert opinion: If current Phase-3 trials are positive, 5-HT6 
antagonists such as Idalopirdine and Intepirdine may be considered as 
supplementary treatments to ChEI's and NMDA receptor antagonists for the 
symptomatic treatment of AD.