This patient is presenting with a medical emergency: an extreme form of thyrotoxicosis known as “thyroid storm.” The symptoms of this syndrome are due primarily to increased β-adrenergic out- flow stimulated by thyroid hormones. After primary stabilization (airway, breathing, and circulation), propylthiouracil or methimazole is the most appropriate pharmacologic treatment for this condition. These agents inhibit the endogenous synthesis of thyroxine, which can cause or worsen this condition.
Answer A is incorrect. Aspirin displaces thyroxine from thyroid-binding globulin and can thus worsen the symptoms of thyrotoxicosis. In contrast, acetaminophen is useful as an antipyretic in the treatment of thyrotoxicosis and thyroid storm.
Answer B is incorrect. Dobutamine is a β- adrenergic agonist that is useful in the treatment of acute congestive heart failure but would exacerbate the adrenergic effects of high-output congestive heart failure secondary to thyrotoxicosis. A β-adrenergic antagonist such as propranolol would be more appropriate in the treatment of thyrotoxicosis.
Answer C is incorrect. Iodine, which decreases the release of preformed thyroxine, can be used as an adjunct to propylthiouracil or methimazole but should not be used until one of these agents is allowed to take effect. Iodine can stimulate the endogenous synthesis of thyroxine and thus exacerbate this condition.
Answer D is incorrect. Levothyroxine, a synthetic form of thyroid hormone, is contraindicated in the treatment of thyrotoxicosis. The addition of more thyroid hormone to a patient with a condition of symptomatic hyperthyroid- ism would only worsen the condition.