Hyperparathyroidism Treatment

• Goal: Normalize calcium levels
• Recommended for the following individuals:
  
  • Mildly elevated serum calcium levels (<1 mg/dL above upper normal limit)
  • No previous life-threatening hypercalcemic episodes
  • Normal bone & renal status
  • Clinically asymptomatic, >50 years old
  • Poor surgical candidate
  • Inability to undergo surgery
  • Patient preference

Bisphosphonates

• Potent inhibitor of bone resorption
• Useful to improve low bone mass in patients w/ untreated PHPT
• Recommended for patients w/ PHPT & osteoporosis or those w/ low bone mineral density warranting intervention who opted not to undergo surgery
• Increases bone mineral density after short term (2 years) therapy
• Alternative treatment in mild hypercalcemia due to PHPT

Alendronate

• Given to patients w/ mild PHPT for 1-2 years
• Increased bone density at the hip & lumbar spine but not radius
• Studies showed 10 mg/day Alendronate effectively reverses bone loss in hyperparathyroidism

Pamidronate

• Most effective for acute treatment of hypercalcemia associated w/ PHPT
• Given intravenously
• Cannot be used as long-term treatment due to poor gastrointestinal drug absorption,
• PTH levels increases w/ increased renal tubular resorption & gastrointestinal calcium absorption

Calcimimetic

• Inhibits PTH secretion by activating calcium-sensing receptor in parathyroid gland
• Used for poor surgical candidates to normalize serum calcium in patients w/ severe hypercalcemia
• Preferred over bisphosphonates for patients who are unable to have surgery & whose primary indication for surgery is symptomatic &/or severe hypercalcemia w/ normal bone density

Cinacalcet

• Approved use in PHPT
• Only approved calcimimetic for secondary hyperparathyroidism treatment
• Used to treat hyperparathyroidism in ESRD patients on long-term dialysis
• Oral administration peaks within 2-3 hours which lowers circulating PTH levels within the same period
• Reduces serum calcium levels in PTCA patients particularly in unresectable diseases & those who underwent multiple operations without cure

Vitamin D & Analogues

• Aggressive supplementation is recommended for secondary hyperparathyroidism patients due to vitamin D deficiency w/ normal renal function
• Helps in suppression of the synthesis of PTH
• Inhibits evolution of parathyroid hyperplasia
• Adequate daily intake of 200 IU, 400 IU & 600 IU are recommended for adults up to 50 years, 51-70 years & ≥71 years respectively
• For patients w/ vitamin D deficiency, 50,000 IU weekly for 8 weeks or 3000 IU daily Vitamin D₂ supplementation or 1000 IU daily Vitamin D₃ is recommended
• Caution must be observed as to high doses can lead to hypercalcemia
• Vitamin D analogues (Paricalcitol & Doxercalciferol) are less likely to cause hypercalcemia