Metrifonate is a cholinesterase inhibitor with a long-lasting inhibition that raises brain acetylcholine levels. It is well-absorbed and has limited binding to serum proteins. In preliminary studies of its utility in the treatment of Alzheimer disease's (AD), it led to improvements of cognition or reduced the rate of decline of cognition compared with placebo. It also benefited the global function of these patients. Side effects include nausea, cramping, and diarrhea. Metrifonate has promise as a well-tolerated treatment of the symptoms of AD.