Phenactin AA Plus 186 Calories Per Carton. Phenactin AA Plus is a specially formulated ready to drink prescription medical food for the clinical dietary management of phenylalanine hydroxylase deficiency (phenylketonuria or PKU) and hyperphenylalanemia.Phenactin AA Plus is to be used only under medical supervision. Phenactin AA Plus has been developed, labeled and should be administered in accordance with the Food and Drug Administrations (FDAs) regulatory definition of Medical Foods.