Bones 2
A 67 yr-old man with chronic kidney disease was found to have an elevated serum PTH conmcentration and a low serum concentration of 25-hydroxyvitamin D. He was successfully treated with ergocalciferol. Unfortunately, his kidney disease progressed so that he required dialysis and his serum PTH concentration became markedly elevated.
Questions and tasks:
1. Which of the following drugs is most likely to lower this patient`s serum PTH concentration?
a. Calcitriol
b. Cholecalciferol
c. Furosemide
d. Gallium nitrate
e. Risedronate
2. Although the drug therapy was effective at lowering serum PTH concentrations, the patient experienced several episodes of hypercalcemia. He was switched to a vitamin D analog that suppresses PTH with less risk of hypercalcemia. Which drug was the patient switched to?
a. Calcitriol
b. Cholecalciferol
c. Furosemide
d. Paricalcitol
e. Risedronate
3. In the treatment of patients like this with secondary hyperparathyroidism due to chronic kidney disease, cinacalcet is an alternative to vitamin D-based drugs. Cinacalcet lowers PTH by which of the following mechanisms?
a. Activating a steroid receptor that inhibits expression of the PTH gene
b. Activating the calcium-sensing receptor in parathyroid cells
c. Activating transporters in the GI ract that are involved in calcium absorption
d. Inducing the liver enzyme that converts vitamin D3 to 25-hydroxyvitamin D3
e. Inhibiting the farnesyl pyrophosphate synthase found in osteoclasts