Treatment of secondary hyperparathyroidism in patients with chronic kidney disease (CKD) on dialysis; treatment of hypercalcemia in patients with parathyroid carcinoma
Increases the sensitivity of the calcium-sensing receptor on the parathyroid gland thereby, concomitantly lowering PTH and serum calcium levels.
Note: Do not titrate dose more frequently than every 2-4 weeks.
Secondary hyperparathyroidism: Oral: Initial: 30 mg once daily (maximum daily dose: 180 mg); increase dose incrementally (60 mg, 90 mg, 120 mg, 180 mg once daily) as necessary to maintain iPTH level between 150-300 pg/mL.
Parathyroid carcinoma: Oral: Initial: 30 mg twice daily (maximum daily dose: 360 mg daily as 90 mg 4 times/day); increase dose incrementally (60 mg twice daily, 90 mg twice daily, 90 mg 3-4 times/day) as necessary to normalize serum calcium levels.
Hyperparathyroidism: Serum calcium and phosphorus levels prior to initiation and within a week of initiation or dosage adjustment; iPTH should be measured 1-4 weeks after initiation or dosage adjustment. After the maintenance dose is established, monthly calcium and phosphorus levels and iPTH every 1-3 months are required. Wait at least 12 hours after dose before drawing PTH levels.
Parathyroid carcinoma: Serum calcium levels prior to initiation and within a week of initiation or dosage adjustment; once maintenance dose is established, obtain serum calcium level every 2 months.
CKD K/DOQI guidelines definition of stages; chronic disease is kidney damage or GFR <60 mL/minute/1.73 m2 for ≥3 months:
Stage 2: GFR 60-89 mL/minute/1.73 m2 (kidney damage with mild decrease GFR)
Stage 3: GFR 30-59 mL/minute/1.73 m2 (moderate decrease GFR)
Stage 4: GFR 15-29 mL/minute/1.73 m2 (severe decrease GFR)
Stage 5: GFR <15 mL/minute/1.73 m2 or dialysis (kidney failure)
Target range for iPTH: Adults:
Stage 3 CKD: 35-70 pg/mL
Stage 4 CKD: 70-110 pg/mL
Stage 5 CKD: 150-300 pg/mL
Serum phosphorus: Adults:
Stage 3 and 4 CKD: ≥2.7 to <4.6 mg/dL
Stage 5 CKD: 3.5-5.5 mg/dL
Serum calcium-phosphorus product: Adults: Stage 3-5 CKD: <55 mg2/dL2