This monograph describes a medication approved for use in Canada by the Therapeutic Products Directorate, a division of Health Canada’s Health Products and Food Branch. The medication is not approved by the United States Food and Drug Administration; however, a similar formulation carrying a different generic or brand name might be available in the US.
vitamin d analogues
Management of hypocalcemia, secondary hyperparathyroidism and osteodystrophy associated with chronic renal failure.
Improved calcium and phosphorus homeostasis in patients with chronic kidney disease.
Absorption: Completely absorbed following oral administration.
Protein Binding: Extensively protein bound.
Metabolism and Excretion: Following absorption, 50 % is rapidly converted by liver to active metabolite (1.25–(OH)2D; 13% renally excreted.
Half-life: 3 hr.
TIME/ACTION PROFILE (levels of active metabolite)
|PO||6 hr||12 hr||few days–1 wk|
|IV||unknown||4 hr||few days–1 wk|
Use Cautiously in:
CNS: headache, drowsiness, weakness
CV: ARRHYTHMIAS, hypertension
EENT: conjunctivitis, photophobia
GI: constipation, nausea, anorexia, dry mouth, metallic taste, pancreatitis, polydipsia, vomiting
F and E: HYPERCALCEMIA, hyperphosphatemia, hyperthermia, ↑ thirst
GU: albuminuria, hypercalcuria, ↓ libido, nocturia, polyuria
Metabolic: ectopic calcification, hypercholesterolemia, hyperthermia
MS: bone pain, muscle pain
* CAPITALS indicate life-threatening.
Underline indicate most frequent.
PO (Adults) Pre-dialysis patients–0.25 mcg/day for 2 mo initially, if necessary dose increments of 0.25 mg/day may be made at 2 mo intervals (usual range 0.5–1.0 mcg/day); dialysis patients –1 mcg/day, if necessary dose increments of 0.5 mcg/day may be made at 2–4 wk intervals (usual range 1–2 mcg/day, up to 3 mcg/day). When normalization occurs, dose should be ↓ to minimum amount required to maintain normal serum calcium levels.
IV (Adults) Dialysis patients–1 mcg during each dialysis session (2–3 times weekly), if necessary dose may be ↑ weekly by 1 mcg per dialysis session up to 12 mcg/wk (range 1.5–12 mcg/wk). When normalization occurs, dose should be ↓ to minimum amount required to maintain normal serum calcium levels.
Soft gel capsules: 0.25 mcg, 1 mcg
Oral drops: 2 mcg/mL
Solution for injection (contains ethanol and propylene glycol): 2 mcg/mL
Lab Test Considerations:
For pre-dialysis patients: Monitor serum calcium and phosphate levels monthly and electrolytes periodically during treatment. For dialysis patients: Monitor serum calcium at least twice weekly during dose titration. If hypercalcemia occurs decrease dose of alfacalcidol by 50% and stop all calcium supplements until calcium levels return to normal. May cause ↑ plasma phosphorous levels. Maintain serum phosphate levels <2.0 mmol/L. Monitor inorganic phosphorus, magnesium, alkaline phosphatase, creatinine, BUN, 24-hour urinary calcium and protein as needed.
Toxicity is manifested as hypercalcemia, hypercalciuria, and hyperphosphatemia. Assess for appearance of nausea, vomiting, anorexia, weakness, constipation, headache, bone pain, and metallic taste. Later symptoms include polyuria, polydipsia, photophobia, rhinorrhea, pruritus, and cardiac arrhythmias. Notify health care professional immediately if these signs of hypervitaminosis D occur. Treatment usually consists of discontinuation of alfacalcidol, a low-calcium diet, stopping calcium supplements. Persistent or markedly elevated serum calcium levels in hemodialysis patients may be corrected by dialysis against a calcium-free dialysate.
Improved levels of calcium and phosphorous in patients with kidney disease.
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