MY HUSBAND WAS ON NAMENDA XR FOR APROX A YEAR, THE INSURANCE COMPANY SAID IT WAS TOO EXPENSIVE AND HE WAS TO TAKE DONEPEZIL HCL 23MG ONCE DAILY, WELL HE IS GETTING WORSE, CANT SLEEP, BAD DREAMS, HEADACHES, TIRED ALL THE TIME. IS THIS NORMAL? HE IS TAKING THE MEDICINE FOR EARLY STAGE ALHEIMERS