Question

A 16-year-old female with a history of goiter is admitted with fever, profuse sweating, tachyarrhythmia, hypertension, abdominal pain, and anxiety. Based on a working diagnosis of thyrotoxicosis, she is started on a beta-adrenoceptor antagonist that has a very short half-life.

. Refer to the case above. Regarding the mechanism by which the drug ameliorates the toxic effects of excessive thyroxine levels, the drug acts as
A) a physiologic antagonist.
B) a competitive receptor antagonist.
C) a noncompetitive receptor antagonist.
D) a partial agonist.
E) an inverse agonist.

Answer 1

The drug acts as a competitive receptor antagonist to ameliorate the toxic effects of excessive thyroxine levels in thyrotoxicosis.

Step-by-step explanation:

The drug acts as a a competitive receptor antagonist to ameliorate the toxic effects of excessive thyroxine levels in thyrotoxicosis. It competes with thyroxine for binding to the beta-adrenoceptor, blocking the receptor and preventing the effects of the excessive thyroxine levels. By acting as a competitive antagonist, the drug helps to normalize heart rate and blood pressure, reducing the tachyarrhythmia and hypertension associated with thyrotoxicosis.