The ambulatory approach to managing hyperthyroidism and hypothyroidism may have to be modified for hospitalized patients. Being strictly nil per os (NPO, nothing by mouth) and disease severity are two of the foremost commonly encountered challenges. For hyperthyroidism, parenteral commercial formulations of beta-blockers and glucocorticoids are universally available. However, thionamides, the mainstay of managing hyperthyroidism, are only manufactured as oral tablets, and parenteral iodide salts, such as NaI, are not presently commercially available. In the United States, patients with hypothyroidism may be treated with intravenous levothyroxine and liothyronine. Due to the expense and the difficulty obtaining these formulations outside of the United States, alternative routes of administration may be required. This section will address managing hospitalized hyperthyroid and hypothyroid patients, focusing on those who are NPO. Many of the recommendations require access to a sophisticated inpatient pharmacy system that is capable of preparing noncommercially available formulations.