Sodium metatungstate (Sodium polyoxotungstate) is a NTPDase inhibitor, with Ki values of 2.58 µM, 3.26 µM, and 28.8 µM for NTPDase 1 (CD39), NTPDase 3 and NTPDase 2 respectively[1]. Sodium metatungstate has anti-inflammatory and anti-cancer effect. Sodium metatungstate inhibits ATP breakdown but also blocks central synaptic transmission[1][2][3][4].