What medication is used to treat hyperparathyroidism?

Medications for Hyperparathyroidism Treatment

For hyperparathyroidism, the primary medications include calcimimetics (cinacalcet), active vitamin D analogs (calcitriol or alfacalcidol), and phosphate binders, with the specific choice depending on the type of hyperparathyroidism and its severity. 1, 2

Treatment Algorithm Based on Type of Hyperparathyroidism

Secondary Hyperparathyroidism (most common)

First-line medications:

• Active vitamin D analogs:
  • Calcitriol: Initial dose 20-30 ng/kg daily
  • Alfacalcidol: Initial dose 30-50 ng/kg daily
  • For patients >12 months: Can start empirically at 0.5 μg daily of calcitriol or 1 μg of alfacalcidol 1

Second-line medication (if PTH remains elevated despite vitamin D):

• Cinacalcet (calcimimetic):
  • Starting dose: 30 mg once daily
  • Titration: Every 2-4 weeks through sequential doses of 30,60,90,120, and 180 mg once daily
  • Target: iPTH levels of 150-300 pg/mL 2

Phosphate management:

• Phosphate binders if hyperphosphatemia is present
• Phosphate supplements (in specific conditions like X-linked hypophosphatemia)

Primary Hyperparathyroidism

• Cinacalcet:
  • Starting dose: 30 mg twice daily
  • Titration: Every 2-4 weeks through sequential doses of 30 mg twice daily, 60 mg twice daily, 90 mg twice daily, and 90 mg 3-4 times daily as necessary
  • Goal: Normalize serum calcium levels 2

Parathyroid Carcinoma

• Cinacalcet: Same dosing as primary hyperparathyroidism 2

Medication Selection Based on Clinical Parameters

For elevated PTH with normal calcium:

• Start with active vitamin D (calcitriol or alfacalcidol)
• Monitor calcium levels closely to avoid hypercalcemia

For elevated PTH with high calcium:

• Cinacalcet is preferred as it lowers both PTH and calcium levels
• Starting dose: 30 mg daily, titrate as needed 2, 3

For persistent secondary hyperparathyroidism despite vitamin D:

• Add cinacalcet to existing vitamin D therapy
• Monitor for potential hypocalcemia 1, 4

Monitoring and Dose Adjustments

• Measure serum calcium and phosphorus within 1 week of starting or adjusting medication
• Check iPTH levels 1-4 weeks after initiation or dose adjustment
• For secondary hyperparathyroidism: Monitor calcium monthly
• For primary hyperparathyroidism or parathyroid carcinoma: Monitor calcium every 2 months 2

Management of Adverse Effects

Hypercalcemia (with vitamin D therapy):

• Reduce or discontinue active vitamin D
• Consider adding cinacalcet

Hypocalcemia (with cinacalcet):

• If calcium <8.4 mg/dL but >7.5 mg/dL: Increase calcium-containing phosphate binders or vitamin D
• If calcium <7.5 mg/dL: Withhold cinacalcet until calcium reaches ≥8.0 mg/dL 2

Secondary hyperparathyroidism with elevated PTH:

• Increase active vitamin D dose and/or decrease phosphate supplements
• Consider adding cinacalcet if PTH remains elevated 1

Important Considerations and Pitfalls

• Cinacalcet is not indicated for patients with CKD who are not on dialysis due to increased risk of hypocalcemia 2
• Excessive doses of phosphate supplements (>80 mg/kg daily) can cause gastrointestinal discomfort and worsen hyperparathyroidism 1
• Parathyroidectomy should be considered for tertiary hyperparathyroidism (persistent hypercalcemic hyperparathyroidism) despite optimized medical therapy 1
• Early treatment with cinacalcet in hemodialysis patients with secondary hyperparathyroidism can increase the proportion of patients achieving target PTH levels with lower doses 3

Special Situations

Tertiary Hyperparathyroidism:

• Trial of cinacalcet with vitamin D
• If unsuccessful, parathyroidectomy is recommended 1, 5

Patients after renal transplantation:

• Cinacalcet can effectively reduce iPTH and serum calcium
• Use higher doses with caution due to potential risk of calciuria, which could favor nephrocalcinosis 6

By following this medication algorithm for hyperparathyroidism, clinicians can effectively manage PTH levels while minimizing complications related to calcium and phosphorus metabolism.