五水合硫酸司巴丁抑制劑Sparteine, a class 1a antiarrhythmic agent, is a sodium channel blocker. It is an alkaloid and found from the scotch broom. It is the main alkaloid in Lupinus mutabilis, and is thought to chelate the magnesium and bivalents calcium. It is not FDA approved for human use as an antiarrhythmic agent, and it is not contained in the Vaughn Williams classification of antiarrhythmic medicines.