Carsatrin succinate is the salt form of Carsatin, a purinylpiperazine derivative used as a cardiotonic and antiarrhythmic. Carsatrin acts as positive inotropic agent that increases twitch tension and prolongs the action potential (AP) duration of ventricular muscle without affecting the Na+, K+-ATPase, adenylyl cyclase, phosphodiesterase isozymes, or cardiac myofilaments. Carsatrin’s positive inotropic effect can be prevented by tetrodotoxin but not by the adrenergic antagonists timolol, yohimbine, or prazosin.