alfacalcidol at a glance
Medicine class
Vitamin D analogue
Main effect
Raises calcium and phosphate availability and can reduce parathyroid hormone activity
Available forms
Soft capsules, oral drops and intravenous injection
Important monitoring
Regular blood tests are needed to detect excess calcium or phosphate and changes in kidney function
What is alfacalcidol used for?
Selected products are licensed for disorders in which calcium metabolism is disturbed because vitamin D activation is impaired or vitamin D resistance is present.
Renal osteodystrophy associated with impaired kidney function
Hyperparathyroidism with bone disease
Hypoparathyroidism
Neonatal hypocalcaemia, for selected drops and injection
Nutritional or malabsorptive rickets and osteomalacia
Vitamin D-dependent pseudo-deficiency rickets and osteomalacia
Hypophosphataemic vitamin D-resistant rickets and osteomalacia
Post-menopausal or glucocorticoid-associated osteoporosis when bisphosphonates are unsuitable or not tolerated, for selected capsules
How does alfacalcidol work?
The liver converts alfacalcidol into calcitriol, the active form of vitamin D. Calcitriol increases calcium and phosphate absorption and helps regulate parathyroid hormone. Unlike ordinary vitamin D supplements, alfacalcidol does not require activation by the kidneys.
alfacalcidol preparations and strengths
Capsule
Route: Oral
Strengths: 0.25 micrograms, 0.5 micrograms, 1 micrograms, 1.0 micrograms
How to take alfacalcidol
Use the prescribed product exactly as labelled; capsules, drops and injection are not interchangeable without clinical review.
Capsules are taken by mouth.
Measure oral drops only with the integral dropper supplied.
The injection is administered intravenously by a healthcare professional.
Check the product and strength carefully whenever a new supply is received.
alfacalcidol side effects
Common or expected effects
- Raised blood calcium or phosphate
- Raised calcium in the urine
- Abdominal pain or discomfort
- Itching or rash
Get urgent medical advice
- Symptomatic hypercalcaemia, which may cause confusion, marked thirst, frequent urination, weakness, nausea, vomiting or drowsiness
- Kidney stones, calcium deposits or worsening kidney function
- Severe allergic reaction, including facial or throat swelling and breathing difficulty
alfacalcidol in pregnancy
Selected product information does not recommend alfacalcidol during pregnancy because human data are limited and high-exposure animal studies found reproductive toxicity. Pregnancy, planned pregnancy or an unplanned pregnancy requires prompt specialist or prescriber review rather than stopping treatment independently.
alfacalcidol while breastfeeding
Alfacalcidol may increase active vitamin D in breast milk and affect the infant’s calcium metabolism. Specialist assessment is advised; if treatment continues, the breastfed infant may need monitoring for hypercalcaemia.
alfacalcidol interactions
Check prescribed, purchased and complementary products for these clinically relevant interactions.
Other vitamin D products or analogues
Additive effects increase the risk of hypercalcaemia; concurrent use generally requires specialist oversight.
Calcium-containing products and thiazide diuretics
These can further increase blood calcium, requiring closer biochemical monitoring.
Common questions about alfacalcidol
Answers are fully visible for fast scanning and source review.
Is alfacalcidol the same as ordinary vitamin D?
No. It is a vitamin D analogue that the liver rapidly converts to calcitriol, whereas common supplements such as colecalciferol require activation by both the liver and kidneys.
Why are blood tests needed with alfacalcidol?
The tests show whether treatment is controlling mineral metabolism without causing excess calcium, phosphate or kidney impairment.
What are the warning signs of high calcium?
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.