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Active Vitamin D Analogue Pregnancy: Not recommended during pregnancy or in women of child-bearing potential not using contraception (limited human data; animal studies have shown reproductive toxicity at high doses). Breast-fed infants of alfacalcidol-treated mothers should be monitored closely for hypercalcaemia.

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.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: 1 microgram daily (initial dose for all indications, adults and adolescents). Elderly: 0.5 microgram daily. Maintenance doses are generally in the range 0.25 to 1 microgram per day; most adult patients respond to doses between 1 and 3 micrograms per day.
Route: Oral — soft capsules swallowed whole with a sufficient amount of fluid
Frequency: Once daily
Adjust the dose thereafter to avoid hypercalcaemia according to the biochemical response (plasma calcium ideally corrected for protein binding, alkaline phosphatase, parathyroid hormone, plus radiographic/histological investigations). Measure plasma levels weekly initially; the daily dose may be increased by increments of 0.25-0.5 microgram; once the dose is established measure calcium, phosphate and creatinine every 2-4 weeks. If hypercalcaemia occurs, stop alfacalcidol until plasma calcium returns to normal (approximately 1 week) then restart at half the previous dose. Indication-specific notes from §4.2: hypoparathyroidism — severe hypocalcaemia is corrected more rapidly with higher doses (e.g. 3-5 micrograms) together with calcium supplements; hyperparathyroidism pre-parathyroidectomy — treat for 2-3 weeks pre-operatively and continue until plasma alkaline phosphatase falls to normal or hypercalcaemia occurs; renal bone disease — consider phosphate binding agents before and during treatment to prevent hyperphosphataemia.

Paediatric dose

Dose: 0.05 microgram/kg
Route: Oral
Frequency: Per day (children from 6 years of age and under 20 kg bodyweight)
Max: Not stated in source
UNIT IS MICROGRAMS, NOT MILLIGRAMS. Exact SPC wording (§4.2): 'Children from 6 year of age and under 20 kg bodyweight: 0.05 microgram/kg/day'. Children over 20 kg bodyweight receive the same initial dose as adults and adolescents (1 microgram/day). Dose is then titrated to biochemical response to avoid hypercalcaemia; serum calcium, phosphate and creatinine should be monitored regularly, especially in children. Verify against a children's formulary before use.

Dose adjustments

Renal

No fixed dose reduction is specified. In patients with renal bone disease or severely reduced renal function a phosphate binding agent could be used simultaneously to prevent increased serum phosphate and potential metastatic calcification; frequent plasma calcium measurements are particularly important in chronic renal failure because prolonged hypercalcaemia may aggravate the decline of renal function. Monitor serum calcium, phosphate and creatinine regularly in renal impairment.

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Paediatric weight-based calculator

UNIT IS MICROGRAMS, NOT MILLIGRAMS. Exact SPC wording (§4.2): 'Children from 6 year of age and under 20 kg bodyweight: 0.05 microgram/kg/day'. Children over 20 kg bodyweight receive the same initial dose as adults and adolescents (1 microgram/day). Dose is then titrated to biochemical response to avoid hypercalcaemia; serum calcium, phosphate and creatinine should be monitored regularly, especially in children. Verify against a children's formulary before use.

Verify in a children's formulary

Contraindications

  • Hypersensitivity to the active substance, arachis oil (peanut oil), soya or to any of the excipients
  • Hypercalcaemia
  • Metastatic calcification

Side effects

  • Hypercalcaemia (common) — symptoms include headache, weakness, anorexia, weight loss, nausea, vomiting, diarrhoea, constipation, polyuria, polydipsia, muscle and bone pain, metallic taste
  • Hyperphosphataemia (common)
  • Abdominal pain and discomfort (common)
  • Rash and pruritus (common)
  • Hypercalciuria (common); nephrolithiasis/nephrocalcinosis and renal impairment including acute renal failure (uncommon)

Interactions

  • Digitalis glycosides — concurrent use in the presence of hypercalcaemia due to vitamin D administration increases the potential for cardiac arrhythmias and is therefore contraindicated; patients taking digitalis and alfacalcidol concomitantly should be frequently monitored with ECG and measurements of plasma digitalis glycoside and calcium levels
  • Thiazide diuretics and calcium-containing preparations — use with caution as there may be an increased risk of hypercalcaemia; monitor calcium levels
  • Other vitamin D-containing preparations — vitamin D or its analogues should not be given concurrently (§4.5 text truncated in the fetched bundle; clinician to confirm the remainder of §4.5)

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. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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