I am 70 with major insomnia for over a year. Have some kind of endogenous sympathomimetic substance that raised my heart rate from 60 to 90, controlled with b-blocker, then major cardiac palpitations with PVCs, found to prevented by low tyramine (and tyrosine) diet. Co cant take anything with Benadryl of similar products. Normal starting dose of Ativan or Ambien seemingly have no effect, although discontinued after only 3-4 days. Any advise?