The opiate analgetic promedol and non-opiate analgetics analgin, clonidine, baclofen, tolibut, vasopressin and calcitonin given in adequate doses block the inward electrosensitive sodium transmembrane ionic current of neurons. Like some drugs which do not exhibit any analgetic effect, promedol, analgin, clonidine, vasopressin and calcitonin also block the electrosensitive delayed potassium current. It is assumed that the blocking of the sodium ionic current may be one of the potential analgetic mechanisms at the neuronal level.