Donna, My name is Randy Thompson and my wife Donna also has PPMS with the trigeminal neuralgia.  The trileptal that she took for the TGN made her drowsy and weak.  Can't say much about the treatment for the PPMS.  But, my wife has had a Gamma Knife procedure for the TGN with some initial success - Pain relief lasted about a year.  She is now lined up for a Cyber Knife procedure.  The Cyber Knife procedure is just like the Gamma Knife procedure - But, less invasive - No skull pins or halo.  Both procedures are essentially the same - The trigeminal nerve is iradiated with gamma rays - No cutting or surgery per-se.  We were told that the procedure could and has eliminated the TGN for many patients and for some the procedure may have to be repeated.  The procedure is usually done by a neurosurgeon and a radiologist.  It's someting that you and your husband may want to look in to.  Randy in Fountain, CO.