Vitamin D + Secondary Hyperparathyroidism Medications Flashcards
What causes hyperparathyroidism?
Hyperphosphatemia and the kidney’s inability to activate vitamin D leads to a decrease in calcium serum concentrations. This triggers the parathyroid gland to secrete more PTH to increase calcium mobilization from the bone.
Which forms of Vitamin D require activation?
Ergocalciferol (Calciferol) -Vitamin D2
Cholecalciferol -Vitamin D3
What is the dosing of Ergocalciferol (Calciferol)?
One 50,000 IU capsule per month
What is the dosing of Cholecalciferol?
1000 IU po daily
What forms of Vitamin D do not require activation?
Calcitriol (Rocaltrol and Calcijex)
Paricalcitol (Zemplar)
Doxercalciferol (Hectorol) **must be activated by liver
What are important considerations for using Calcitriol (Rocaltrol and Calcijex)
-Approved for pediatric use
-Greatest risk of hypercalcemia
-Cheapest
Monitor: Ca, iPTH
What are important considerations for using Paricalcitol (Zemplar)?
30% reduction in iPTH
-Most favorable adverse drug reaction profile
-Less calcemic activity than calcitriol
Monitor: Ca, iPTH
What are some important considerations for using Doxercalciferol (Hectorol)?
-It is a prodrug that must be activated by the liver!!
-Lets the patient’s body activate it as it needs it
-Produces more even serum concentration that calcitriol
-30% reduction in iPTH
-Lower incidence of hypercalcemia compared to calcitriol
-Higher incidence of hyperphosphatemia
*Do not use in patients with both kidney and liver failure
*Mainly used when phosphorus is not high and we just want to bring the PTH down
What are the two calcimimetic drugs?
Cinacalcet (Sensipar)
Etelcalcetide (Parsabiv)
*Cinacalcet is prefered since Etelcalcetide is an IV drug
What is the mechanism of action for Cinacalcet (Sensipar)?
Type II calcimimetic agent
-Mimics the action of calcium by binding to the calcium sensing receptor (CaR) and inducing a conformational change to the receptor. This triggers the parathyroid gland to decrease PTH secretion.
-Binds irreversibly, when calcium drops below 7.5 mg/dL we must stop the drug and wait for new receptors to form
What is the dosing of Cinacalcet (Sensipar)?
30mg po once daily
-Increase dose to achieve desired PTH serum concentrations
-MAX DOSE: 180mg
When are calcimimetics contraindicated?
Contraindicated in hypocalcemia
If Ca < 7.5mg/dL, withhold calcimimetics until Ca = or > 8mg/dL
Which of the following vitamin D products DOES NOT require activation by a body organ prior to activation?
A. calcitriol
B. doxercalciferol
C. cholecalciferol
D. ergocalciferol
A. calcitriol
Mrs. Jenkins is an 82 year old hemodialysis patient who presented to the clinic today with persistent secondary hyperparathyroidism. Her most current labs are as follows:
Ca 7.2 mg/dL (L)
Phos 4.0 mg/dL
PTH 1300 pg/mL (H)
Vitamin D 35 ng/mL
Which of the following medications should be recommended for treating her secondary hyperparathyroidism?
A. cholecalciferol
B. ergocalciferol
C. cinacalcet (Sensipar)
D. paricalcitol (Zemplar)
D. paricalcitol (Zemplar)
