Quinacainol (also known as PK 10139 or RP 54272) is a quinolinemethanol derivative patented by Pharmindustrie as an antiarrhythmic agent. Quinacainol acts as a sodium channel antagonist and demonstrated both class Ia and Ic antiarrhythmic properties. Quinacainol blocked sodium currents in a concentration-dependent manner and with a potency similar to that of quinidine. Quinacainol produces a slowing of action potential conduction, consistent with a block of sodium channels, and a slight prolongation of action potential duration, consistent with a block of potassium currents.