seizures
"I am now 78 yrs old.  Have taken 15mg in AM, 30mg at PM since 1960's.   December 13 Neurologist told me to eliminate the AM, take only PM.  'Because it might affect my liver.'  Dizziness on December 18,19, 20.  December 21, chest pains, December 23 to ER for chest pains.  Given Imdur.  ER scheduled Stress Test,  It showed no heart condition.  Dec 30,chest pains again.  ER doctor suggested med for Vertigo. Slight relief.  Cardiologist suggested a MRI but suspected it was  withdrawal of Phenobarbital. Cardiologist said to contact Neurologist who did not return my call 'because she was on vacation.'  Pharmacist called her office, got original  Phenobarbital and I felt immediate relief.  Lesson: you know your own body!"