NCIt definition : The hydrochloride salt form of tocainide, a primary amine analog of lidocaine exhibiting
class 1b antiarrhythmic property. Tocainide hydrochloride stabilizes the neuronal
membrane by reversibly binding to and blocking open and inactivated voltage-gated
sodium channels. This inhibits the inward sodium current required for the initiation
and conduction of impulses and reduces the excitability of myocardial cells. This
agent reduces the rate of rise and amplitude, and shortens the action-potential duration
(APD) in both the Purkinje and muscle fibers. Tocainide also shortens the effective
refractory period (ERP) of Purkinje fibers resulting in an increased the ERP/APD ratio.
Overall these effects lead to the slowing of nerve impulses and stabilization of the
heartbeat.;