The Sound of Evolution
Procainamide
Mechanism of action:
Procainamide is a class IA sodium channel blocker. Procainamide binds to voltage-gated Na+ channels on the membrane of cardiomyocytes, reduces the phase 0 depolarization rate, and slows cardiac conduction, especially in the atria, ventricles, and Purkinje fibers. In addition to sodium channel blockade, procainamide also inhibits part of the outward K+ currents, thereby prolonging action potential duration and extending the effective refractory period.
Reference(s):
1. Chiu PJ et al. (2004). Validation of a [3H]astemizole binding assay in HEK293 cells expressing HERG K+ channels. J Pharmacol Sci.
2. Tobita M et al. (2005). A discriminant model constructed by the support vector machine method for HERG potassium channel inhibitors. Bioorg Med Chem Lett.
3. Liu T et al. (2025). BindingDB in 2024: a FAIR knowledgebase of protein-small molecule binding data. Nucleic Acids Res.