Alfacalcidol – a form of vitamin D prescribed by doctors

Alfacalcidol – a form of vitamin D prescribed by doctors

Alfacalcidol is a form of vitamin D prescribed by doctors. It is primarily used to treat renal bone disease in patients with CKD.

What is alfacalcidol?

• Alfacalcidol is a prescription vitamin D analogue that helps the body maintain normal calcium levels
• It is commonly used in people who cannot activate ordinary vitamin D properly, especially those with chronic kidney disease (CKD)

Unlike standard vitamin D supplements, alfacalcidol works even when kidney function is reduced.

How it works

• The mechanism of action of alfacalcidol involves its conversion in the liver to calcitriol, the active form of vitamin D
• This ‘activated form of vitamin D’ increases calcium and phosphate absorption from the gut, helping to regulate calcium levels in the blood
• This action reduces excessive parathyroid hormone activity, particularly in kidney-related bone disease.

Uses

The main uses of alfacalcidol include treatment of:

• Chronic kidney disease (CKD) – related bone disease
• Hypocalcaemia (low blood calcium levels)
• Hypoparathyroidism
• Osteomalacia and rickets

By improving calcium absorption, alfacalcidol helps reduce bone pain, muscle weakness, and fracture risk.

Dosage

• Adults: 0.25–1 microgram once daily; it can occasionally be used in high dosage (e.g. 5 mcg once a day) – if so, weekly (or daily) bloods (especially calcium) need to be done, under the supervision of a hospital specialist
• Children: Dose adjusted by age and weight
• Elderly patients: Often start on a lower dose (e.g. 0.25 mcg 3x a week)

Note. Patients should avoid extra vitamin D or calcium unless advised.

Side-effects

Most alfacalcidol side-effects are mild but may be linked to raised calcium levels.

• Nausea
• Constipation
• Reduced appetite

Signs of high calcium levels (hypercalcaemia)

• Itching
• Red eyes
• Weakness
• Confusion
• Increased thirst or urination

Such symptoms may indicate dangerous levels of  hypercalcaemia and should be reported to your specialist soon.

Monitoring

Your doctor should monitor:

• Blood calcium levels (may rise)
• Phosphate levels
• Kidney function tests (creatinine and GFR)
• Parathyroid hormone (PTH) levels, if required

Note. Blood tests need to be more frequent when starting or changing the alfacalcidol dose.