Drug potency on inhibiting late Na + current is sensitive to gating modifier and current region where drug effects were measured.

I pharmacology can be impacted by all experimental factors examined in this study. The effect of gating modifier and current region used to quantify drug inhibition alone led to 30× difference in half inhibitory concentration (IC) for ritonavir, demonstrating that substantial difference in drug inhibition can be produced. Drug potencies on inhibiting I derived from different patch clamp studies may thus not be generalizable. For I pharmacology to be useful for in silico modeling or interpreting drug-induced changes in cardiac action potentials or ECG, standardizing I experimental procedures including data analysis methods is necessary to minimize data variability.