In automated patch-clamp pharmacology experiments it is common practice to determine IC50 values. However, in the case of sodium channel inhibitors, IC50 values can differ by several orders of magnitude depending on the holding potential, the duration and frequency of depolarizations, etc. A single IC50 value is completely meaningless, one needs to study state-dependence, onset/offset kinetics, and modulation of gating to assess the mechanism of inhibition. This, however seems to be unfeasible at high throughput in automated patch clamp experiments. We developed a protocol for the IonFlux Mercury instrument which assesses steady-state inactivation, recovery from inactivation, and the onset of drug effect depending on depolarization length; all within 522 ms. The protocol consists of 17 depolarizations, and can be repeated at 1 Hz in all 64 channels. This means that for a drug with an optimally fast onset and offset kinetics 3 s would be enough to perform a complete analysis. In practice of course it was more practical to perfuse individual sodium channel inhibitor compounds for a longer time (30 to 40 s), which allowed us to determine onset and offset time constants for different conditions (holding potentials, frequencies, pulse durations). We found that onset and offset time constants differed even within the same experiment depending on these conditions, which gave an insight into the details of inhibition mechanisms by individual drugs. Raw data were processed using an Octave script (Matlab compatible) to subtract leakage and capacitive artifacts, and to fit steady-state inactivation and recovery plots. The changes in individual peak amplitudes, half-inactivation voltage, and recovery time constants were monitored with 1 s time resolution throughout the experiment. Our approach performs a comprehensive evaluation of drug inhibition mechanisms, providing much more information for the same price of consumables.