Secondary Hyperparathyroidism Drugs Flashcards
What are the characteristics of Cinacalcet (Sensipar)?
Uses: Treatment of 2o hyperPTH in pts with chronic kidney disease (manifests as decreased 1,25 vitamin D synthesis), or treatment of hypercalcemia in pts with PTH carcinoma
MOA: increases sensitivity of Ca sensing receptors in parathyroid gland so that lower levels of extracellular Ca will be more effective in activating the receptors = decreased synthesis and release of PTH and therefore lowers serum Ca levels
What are the characteristics of Paricalcitrol (Zemplar)?
● Uses: Vit D analog indicated for treatment of 2o hyperPTH in pts with chronic kidney disease
● MOA: molecule is formed through removal of carbon atom 19 and modifications to the side chain of calcitriol. This modification results in an active Vit D product that does not require activation by the kidney and that has a “selective” action on the PT gland to lower PTH release , with little or no direct effects on serum Ca or PO 4 levels (because has little or no effect on bone OC’s,intestine,kidney)
● Think of paracacitriol as a selective agonist at the Vit D receptor of the parathyroid gland
● Side effects: Although clinical studies indicate that the incidence of hypercalcemia associated with the use of paracalcitriol is nearly equal to that of placebo, there appears to be a finite risk that the drug can produce hypercalcemia or elevated CaXP product
( which reflects serum Ca and PO 4 levels ) based upon the hypothetical that this drug may not be as selective for PTH vitamin D receptors as assumed ,and therefore might interact with vitamin D receptors in the intestine and or kidney, leading to increased Ca and P in the serum. Because of the hypothetical risk, the drug is absolutely contraindicated in patients with hypercalcemia or hypervitaminDosis (VitD toxicity) due to potential safety concerns
