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Active Vitamin D Analogue

Alfacalcidol (1-alpha-Hydroxycholecalciferol)

Brand names: One-Alpha, Alfacal

Used in: Chronic Kidney Disease

Alfacalcidol (1-alpha-hydroxycholecalciferol) is an activated vitamin D analogue used to treat conditions such as renal osteodystrophy, hypoparathyroidism and vitamin D-resistant rickets.

Dosing — being independently re-sourced

ClinCalc Pro is rebuilding its dose data from primary open sources — the manufacturer SmPC (eMC), the WHO Model Formulary and other official references — under clinician review. This drug's structured dose is not yet published here. Confirm all doses against the product SmPC and your local formulary before prescribing.

Clinical monograph

How it works

It is rapidly hydroxylated in the liver to active 1,25-dihydroxyvitamin D, bypassing renal 1-alpha-hydroxylation, and promotes intestinal calcium and phosphate absorption and normal bone mineralisation.

Prescribing in practice

  • Hypercalcaemia is the principal hazard, so serum calcium must be monitored and the dose adjusted to avoid it, with the risk increased by concurrent calcium or other vitamin D supplements.
  • It is particularly useful in renal impairment because it does not require renal activation, unlike standard colecalciferol.
  • Thiazide diuretics and calcium-containing preparations can potentiate hypercalcaemia and should be used cautiously together.

Monitoring

Monitor serum calcium (and phosphate where relevant) regularly, especially during dose titration, to detect and prevent hypercalcaemia.

Counselling the patient

  • An active form of vitamin D that helps maintain calcium and bone health.
  • Attend for blood tests to check your calcium level as advised.
  • Tell the team before taking additional calcium or vitamin D supplements.

Evidence & guidelines

Alfacalcidol is well established for vitamin D-dependent and renal bone disorders, with hypercalcaemia monitoring described in the SPC and renal guidance.

Reference: NICE CG182 (CKD); KDIGO CKD-MBD Guidelines 2017; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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