A 13-Year-Old Boy Is Brought to the Office by His

A 13-year-old boy is brought to the office by his parents due to their concern about his behavior and academic performance.  The patient is failing several classes in junior high school and has few friends.  His mother reports, "His teachers complain that he doesn't pay attention and disrupts the class.  One teacher says that he clears his throat repeatedly, distracting the other kids and making it difficult for her to teach.  She has asked him to stop but he keeps doing it."  The boy says, "I try in school but the kids are mean and make fun of me because they think I am weird or something."  Over the past year, his father has observed frequent repeated blinking, which he found unusual but assumed was a sign of fatigue.  His mother adds that several months ago the boy was grimacing frequently, but this seems to have passed.  In the office, the boy shrugs his left shoulder repeatedly.  Medical history is unremarkable.  A Stanford-Binet test administered 2 years ago measured the boy's intelligence quotient as 95.  Temperature is 37.2 C (99 F) , blood pressure is 110/70 mm Hg, pulse is 88/min, and respirations are 14/min.  Weight is 45 kg (99.2 lb) and height is 155 cm (5 ft 1 in) .  Physical examination, including neurological examination, is normal. The diagnosis of Tourette syndrome is made.  The physician educates the patient and his parents about the disorder and provides counseling on behavioral techniques to suppress tics.  Six months later, the patient returns with his mother for a follow-up visit.  She reports that the tics are worse and very distressing.  Although his grades have improved somewhat, he is miserable at school and refuses to attend any afterschool activities.  Examination shows grunting, facial grimacing, and writhing of the left side of the body.  Which of the following medications would be most effective in reducing tics in this patient?

A) Ethosuximide
B) Fluoxetine
C) Methylphenidate
D) Risperidone
E) Valproate