A 32-year-old woman presents for follow-up after being presc…

A 32-year-old woman presents for follow-up after being prescribed zolpidem 10 mg nightly for short-term treatment of insomnia. She reports that although the medication helps her fall asleep, she often experiences morning grogginess, impaired concentration at work, and difficulty driving safely the next day. She denies alcohol or other sedative use. Her BMI is 23, and liver and renal function tests are normal. Which pharmacokinetic factor best explains her increased sensitivity to zolpidem? 

A 10-year-old boy with ADHD has been treated with amphetamin…

A 10-year-old boy with ADHD has been treated with amphetamine-dextroamphetamine XR 20 mg daily for the past month. His parents report that while his attention has improved, he has become increasingly irritable, anxious, and emotionally labile, especially in the afternoons. His appetite and sleep are otherwise stable. Physical exam is unremarkable, vitals are normal, and growth parameters are appropriate. What is the most appropriate next step in management?