Phenamil methanesulfonate, an analog of Amiloride , is a more potent and less reversible epithelial sodium channel (ENaC) blocker with an IC50 of 400 nM[2]. Phenamil methanesulfonate is also a competive inhibitor of TRPP3 and inhibits TRPP3-mediated Ca2+ transport with an IC50 of 140 nM in a Ca2+ uptake assay[1]. Phenamil methanesulfonate is an intriguing small molecule to promote bone repair by strongly activating BMP signaling pathway[4]. Phenamil methanesulfonate is used for the research of cystic fibrosis lung disease[5].