Use-dependence Class I drugs bind more rapidly to open or inactivated sodium channels than to channels that are fully repolarized following recovery from the previous depolarization cycle.Therefore,these drugs show a greater degree of blockade in tissues that are frequently depolarizing.This property is called use- dependence
Use-dependence ◼ Class I drugs bind more rapidly to open or inactivated sodium channels than to channels that are fully repolarized following recovery from the previous depolarization cycle. Therefore, these drugs show a greater degree of blockade in tissues that are frequently depolarizing. This property is called usedependence
Quinidine Quinidine is the prototype Class IA drug. At high doses,it can actually precipitate arrhythmias,which can lead to fatal ventricular fibrillation
Quinidine ◼ Quinidine is the prototype Class IA drug. At high doses, it can actually precipitate arrhythmias, which can lead to fatal ventricular fibrillation