By reviewing existing clinical trial and/or MR studies of medication treatment and/or drug repurposing for Alzheimer’s disease (from inception to 1 March 2021), we found some evidence to support the role of liraglutide (a GLP-1 inhibitor) and most of the antihypertensive drugs on preventing/delaying cognitive impairment [37–41]. Here, GCG is linked to early-onset autosomal dominant Alzheimer disease.