A 40-year-old man has been taking fluoxetine (Prozac) for seasonal depression for the past 3 months, as prescribed by his psychiatric-mental health nurse practitioner. He believes his symptoms are well controlled. The patient's primary care provider recently prescribed atorvastatin (Lipitor) for hypercholesterolemia. Today, he complains of muscle and joint pain. The PMHNP suspects possible rhabdomyolysis. Which answer choice describes the reason for this?