increased TSH secretion that inhibits T4 and T3 synthesis. Minimal doses should
be given when indicated to avoid goiter formation.
Strong iodide preparations such as Lugol’s solution are used to suppress
thyroid function in patients having a subtotal thyroidectomy for Graves’s dis-
ease. Sodium iodide administered intravenously is useful for the management of
thyrotoxic crisis.
A list of drugs utilized in the treatment of hyperthyroidism is provided in the
Appendix. Detailed tables show doses, recommendations, expectations, side
effects, contraindications, and more; available on the book’s Web site (see URL
in Appendix).
DRUGS AND THE PARATHYROID GLANDS
The parathyroid glands secrete parathyroid hormone (PTH) that regulate cal-
cium levels in the blood. A decrease in serum calcium stimulates the release of
PTH. A decrease of PTH is called hypoparathyroidism and an increase in PTH
is hyperparathyroidism.
Hypoparathyroidism is treated with PTH drugs and hyperparathyroidism is
treated with calcitonin. Calcitonin decreases serum calcium levels by promoting
renal excretion of calcium.
PTH deficiency can cause hypocalcemia, which is a deficit of serum calcium.
Hypocalcemia can also be caused by vitamin D deficiency, renal impairment, or
diuretic therapy.
Hypocalcemia is treated with PTH replacement that corrects the calcium deficit
by promoting calcium absorption from the GI tract, promotes calcium reabsorp-
tion from the renal tubules, and activates Vitamin D. Calcitriol is a vitamin D
analogue that promotes calcium absorption from the GI tract and secretion of
calcium of bone to the bloodstream.
Hyperparathyroidism is caused by malignancies of the parathyroid glands or
ectopic PTH hormone secretion from lung cancer, hyperthyroidism, or pro-
longed immobility during which calcium is lost from bone.
DRUGS AND THE PANCREAS
The pancreas secretes insulin that is used to metabolize glucose. The patient con-
tracts diabetes mellitus if insufficient insulin is produced. Diabetes mellitus is a
chronic disease resulting from deficient glucose metabolism caused by insufficient
CHAPTER 21 Endocrine Medications^391