A 49-year-old woman presents with a two-year history of chronic low back pain following a workplace injury and a concurrent 14-month history of major depressive disorder. Her PHQ-9 score is 19, and she reports persistent depressed mood, loss of interest, poor concentration, fatigue, and insomnia. Her pain is described as constant, rated 7 out of 10, and has not responded adequately to physical therapy, NSAIDs, or acetaminophen. She is not currently taking any psychotropic medications or opioids. She has been evaluated by orthopedics and pain management, and no surgical intervention is indicated. Her primary care provider notes that the depression and pain seem to be worsening each other and refers her for psychiatric treatment planning. The PMHNP is developing an integrated treatment approach. Which of the following best describes the most appropriate pharmacological strategy for this patient?