PATHOPHYSIOLOGY OF CKD-MBD
Starts with decreased renal elimination of...

serum phosphorus

Hyperphosphatemia associated with increased risk of...
-Can sig impact patient quality of life

CV events, mortality

Serum : Normal Range
Phosphorus:
Calcium:
PTH:

2.7-4.6 mg/dL
8.6-10.3 mg/dL
10-55 pg/mL

NON-PHARM THERAPY OF CKD-MBD
What is the 1st-line therapy?
What else?

Dietary phosphorus restriction
Dialysis
Parathyroidectomy

�Also referred to as "binders"
�Used in conjunction with dietary phosphorus restriction for hyperphosphatemia
�Bind to dietary phosphorus to form insoluble complex --> passed in feces

Phosphate-Binding Agents

What is the first line therapy for high PTH?
-Suppresses PTH synthesis by increasing GI Ca2+ and PO4 absorption

Vitamin D Analogs

�Last line for PTH suppression
�Binds to calcium-sensing receptors (CaSR) to increase sensitivity to Ca2+ --> "mimics" calcium
�Generally not needed until ESKD

Calcimimetics

Adverse effects of Calcimimetics:

n/v, hypocalcemia

Drug-Drug Interactions of calcimimetics?
Should not be started in patients with...

CYP3A4 substrate
CYP2D6 Inhibitor
hypocalcemia

Monitoring of Calcimimetics require close monitoring of calcium, PTH:

1 week after starting
Monthly thereafter

Phosphate-Binding Agents
�Decreases serum phosphorus by binding dietary phosphorus (and preventing it from being absorbed)
�Must be taken...

WITH meals

Adverse effects of Phosphate-Binding agents:

Constipation
N/v
Abdominal pain
Hypercalcemia (calcium-based binders)

Phosphate-Binding Agents
How should oral meds be given to prevent Drug-Drug Interactions?

Give 2 hours BEFORE binder
or
Give 4 hours AFTER binder

Iron-based phosphate binding agents can cause....

darkening of stools

Vitamin D analogs:
Adverse effects:
Drug-Drug Interactions:

hypercalcemia, hyperphosphatemia, over-suppression of PTH
Absorption can be decreased if given with cholestyramine

Which Vitamin D supplement (PO) is preferred in non-dialysis dependent CKD (Stage 3 & 4)

Ergocalciferol (Drisdol)
Cholecalciferol

Which Vitamin D supplement (IV) is used in Stage 5 CKD?
-How are IV formulations dosed?

Calcitriol
Doxercalciferol
Paricalcitol
3x/week