2 weeks аgо а 10-yeаr-оld bоy started Vyvanse (lisdexamfetamine) for ADHD. He takes the medication every morning at 7AM before leaving for school. His attention and hyperactive and impulsive behaviors have improved greatly since starting the medication. However, he has been tired during the day because he's had difficulty falling asleep since starting Vyvanse. Which of the following is an appropriate recommendation?