Dual-acting compounds, inhibitingadditionally AChE or BuChE, prolong the survival time of acetylcholinein the neuronal cleft.31,32 Co-administration of a H3R antagonist (MK-3134) and an AChE inhibitor (donepezil) showeda more pronounced, pro-cognitive outcome than the effects of eachcompound separately.33,34 Dual-acting drugs can be importantfor the treatment of Alzheimer’s disease due to their lowertoxicity, less drug–drug interactions, unified pharmacokineticprofile, and higher efficacy. Here, ACHE is linked to early-onset autosomal dominant Alzheimer disease.