Thyroid Disorders Flashcards
What are the most common thyroid hormone replacements?
Levothyroxine (T4)
Liothyronine (T3)
How do T3 and T4 replacement therapy work?
Binding to intracellular thyroid hormone receptors, activating transcription
What are some side effects of thyroid hormone replacement therapies?
Tachycardia*
Atrial fibrillation*
When is surgery indicated for hyperthyroidism?
When the thyroid is compressing the trachea
How does radioiodine (131I) work?
Radiation destroys the thyroid, causing hypothyroidism
What class of medication are propylthiouracil, methimazole, and carbimazole a part of?
Thioamides
What is the MOA of thioamides?
They prevent thyroid synthesis in one of the following ways:
Inhibit thyroperoxidase
Block iodine oxidation
Block coupling of iodinated tyrosines
Inhibit peripheral deiodination of T4
Requires 3-4 weeks to work due to the nature of the body and thyroid hormones
What are some side effects of thioamide treatment?
Skin rash*
Fever
Arthralgia
Neutropenia*
Agranulocytosis*
Hepatotoxicity
Vasculitis
What is lugol iodine?
A solution of potassium iodide with iodine in water
When is lugol iodine used?
For preparation for surgery
How does lugol iodine work?
Iodide in excess amounts inhibits thyroid hormone secretion, reduces vascularity of the thyroid gland, and may also inhibit iodination of thyroglobulin reducing generation of hydrogen peroxide
How do beta-blockers, such as propanolol, work in hyperthyroidism?
They are used to negate the elevated heart rate associated with hyperthyroidism
Propanolol may also prevent peripheral conversion of T4 to T3
