From the Guidelines
1-alpha hydroxycholecalciferol (alfacalcidol) should be used in patients with impaired 1-alpha hydroxylation in the kidneys, such as those with advanced chronic kidney disease (CKD), hypoparathyroidism, vitamin D-dependent rickets type 1, and osteoporosis requiring active vitamin D supplementation, at a typical adult dosage of 0.25-1 mcg daily, adjusted based on patient response, as recommended by the most recent guidelines 1. The primary benefit of alfacalcidol is its ability to bypass the need for renal activation, directly providing the active form of vitamin D needed for calcium absorption and bone mineralization, which helps prevent renal osteodystrophy, hypocalcemia, and secondary hyperparathyroidism. Some key points to consider when using alfacalcidol include:
- Essential monitoring includes regular serum calcium, phosphate, and parathyroid hormone (PTH) levels, typically every 2-4 weeks initially and then every 3-6 months once stable, as well as renal function and 25-OH vitamin D levels 1.
- Patients should be warned about potential hypercalcemia symptoms (nausea, vomiting, constipation, confusion) and advised to maintain adequate hydration while taking this medication.
- The use of alfacalcidol has been shown to improve bone histology and increase bone mineral density in patients with CKD, and its safety has been established in doses of 0.25-0.5 mcg daily 1.
- However, it is crucial to avoid hypercalcemia and to monitor patients closely for signs of adverse effects, as the safety of alfacalcidol in CKD patients with moderately reduced kidney function is a matter of concern 1.
From the Research
Benefits of 1-alpha hydroxy-cholecalciferol
- 1-alpha hydroxy-cholecalciferol, also known as alfacalcidol, has been shown to have beneficial effects on chronic-kidney disease (CKD-) related bone disease and secondary hyperparathyroidism 2.
- It has been used to treat abnormalities in bone and mineral balance that arise in chronic kidney disease, as it does not require enzymatic activation by the kidneys 2.
- Clinical investigations have also shown that 1 alpha-hydroxycholecalciferol produces a positive clinical effect in different types of osteoporosis and osteomalacia, with clinical improvement noted in 1-2 months and x-ray evidence of bone regeneration in 6-12 months 3.
Monitoring and Precautions
- Monitoring of calcium and phosphorus levels is required after initiation of 1-alpha hydroxy-cholecalciferol, with dose adaptations made accordingly 2.
- Therapy with 1-alpha hydroxy-cholecalciferol should be attended by regular checks for hypercalcemia and hyperphosphatemia, particularly in patients with chronic kidney disease 2, 4.
- The frequency and magnitude of hypercalcemia or hyperphosphatemia observed with 1-alpha hydroxy-cholecalciferol treatment may be less than calcitriol or alphacalcidol therapy but not less than such vitamin D-mimetics as paricalcitol or maxacalcitol 4.
When to Use
- 1-alpha hydroxy-cholecalciferol is a justifiable compound to prescribe to CKD patients with established bone disease or hyperparathyroidism 2.
- It can be used for the treatment of secondary hyperparathyroidism (SHPT) in chronic kidney disease (CKD), particularly if hypercalcemia is of concern 4.
- In cases of vitamin D hydroxylation-deficient rickets type 1A, 1-alpha hydroxy-cholecalciferol may be used to treat the underlying defect in 1α-hydroxylation 5.
- In hypoparathyroidism, the use of 1-alpha hydroxy-cholecalciferol is not well established, but supplementation with parent vitamin D (either ergocalciferol or cholecalciferol) is recommended to provide sufficient 25(OH)D substrate to the residual 1-α-hydroxylase activity 6.