Like yourself, I've been on Dilantin for many years, 52 to be exact and my primary doc does check bone density about every 2 years. I also took phenobarbital for the first 20 years with Dilantin after getting diagnosed. Likely, when neuro docs say this can be a side effect or that can be a side effect, this means possible but no guarantees. I was also warned about side effects of long term use of Dilantin including gum growth which happened to me about 18 years ago. That procedure was no picnic. Several neuro docs have assured me that long term use of Dilantin can't cause balance issues or neuropathy. Even after a half century??