BCHE and Alzheimer disease: On the other hand, results of a systematic review with meta-analysis of the results of 30 RCTs involving 7,567 patients demonstrated that the adamantane analog, memantine (Figure 1) was effective for the improvement of cognitive function in patients with AD compared to placebo, a finding that was highly significant either with or without the addition of cholinesterase inhibitors (Kishi et al., 2017).