Lidocaine, a use-dependent blocker of voltage-gated Na⁺ channels, is an effective antiarrhythmic because its blocking effect becomes greater when: A) The drug is repeatedly used. B) Na⁺channels are activated repeatedly at a high frequency. C) Na⁺ channels are activated repeatedly at a low frequency. D) Na⁺ channels are closed. E) The extracellular Na⁺ concentration is high.

Question

Quizplus · Accepted Answer

Lidocaine's blocking effect on voltage-gated sodium channels increases with higher frequency activation because it preferentially binds to and stabilizes the inactivated state of these channels, which occurs more frequently during rapid firing of action potentials, as seen in arrhythmias.

Lidocaine, a Use-Dependent Blocker of Voltage-Gated Na+ Channels, Is an Effective

Lidocaine, a Use-Dependent Blocker of Voltage-Gated Na⁺ Channels, Is an Effective