This is at best a fallacy with occasional exceptions and in this particular case, just plain incorrect. If it works by 'blocking a compound that supports nerve

This is at best a fallacy with occasional exceptions and in this particular case, just plain incorrect. If it works by 'blocking a compound that supports nerve cells in transmitting pain' it isn't doing anything to correct the pathology. You are, in the truest sense of the way that people naively talk in derogatory terms around modern medicine, 'treating the result, not the cause'