Question

Accompanied by her husband, a 31-year-old architect presents to her primary care physician with complaints of overwhelming fatigue and persistent low mood that began a month ago. She reports spending most of her days in bed, missing work deadlines, and feeling intensely guilty about her lack of productivity. She states, "I just don't see the point in trying anymore." Upon further questioning, her husband recalls an unusual period two years prior. Over a span of 15 days, the patient barely slept, talked continuously about redesigning their entire city, and impulsively purchased $15,000 worth of construction materials. That episode led to severe financial distress and a brief psychiatric hospitalization, after which she returned to her baseline. Laboratory studies show a thyroid-stimulating hormone (TSH) level of 1.1 mU/L (normal: 0.5–5.0 mU/L) and a free T4 level of 0.9 ng/dL (normal: 0.9–1.7 ng/dL). She currently takes no medications. Which of the following is the most appropriate pharmacotherapy to initiate for this patient?