EGFR and Hypokalemia: The case of TKIs that target the epidermal growth factor receptor (EGFR) is paradigmatic: apart from slight PK differences (with CYP3A4 being the main enzyme involved in the metabolism for a number of TKIs-EGFR), diarrhea should be considered a class effect of these drugs and may predispose to dehydration and hypokalemia, thus increasing the likelihood of TdP.