Q. A 32-year-old female presents to the emergency department with a complaint of palpitations, tremors, and weight loss over the past month. She reports feeling anxious and having difficulty sleeping. She has a past medical history of Hashimoto's thyroiditis and has been on levothyroxine for the past year. She reports no other significant medical history and is not regularly taking any other medications. She works at a coffee shop and is married with two children. On physical examination, the patient is alert and oriented with a heart rate of 110/min and a blood pressure of 150/90 mm Hg. She has a diffuse goiter and fine tremors in her fingers. She has no peripheral edema or other notable physical findings. Laboratory values reveal a TSH of 0.01 mIU/L and a free T4 of 5.6 ng/dL. A thyroid ultrasound (see image) shows a diffusely enlarged thyroid gland with multiple hypoechoic nodules. Based on the patient's presentation, laboratory values, and imaging, which of the following medications should be started immediately for symptomatic relief?