Alfacalcidol
Generic Details
Generic Name
Alfacalcidol
Other Names
- 1-alpha-hydroxycholecalciferol
- 1α-hydroxycholecalciferol
Drug Class
- Vitamin D analog
Chemical Formula
C27H44O2
Molecular Weight
400.64 g/mol
Mechanism of Action
- Alfacalcidol is a prodrug of calcitriol, the active form of vitamin D. It is converted in the liver to calcitriol, which then acts on the vitamin D receptor to regulate calcium and phosphate metabolism.
Indications
- Treatment of vitamin D deficiency
- Secondary hyperparathyroidism
- Osteoporosis
- Hypocalcemia associated with hypoparathyroidism
Common Dosage Forms
- Capsules
- Oral drops
Typical Dosage
- 0.25-1 mcg once daily
Pediatric Dosage
- Dosing based on weight and severity of condition
Geriatric Dosage
- Usually lower initial doses due to decreased renal function
Side Effects
- Hypercalcemia
- Hypercalciuria
- GI disturbances (nausea, constipation)
- Headache
- Muscle weakness
Contraindications
- Hypercalcemia
- Vitamin D toxicity
- Hypersensitivity to alfacalcidol or other vitamin D analogs
Pregnancy Category
- Category C - Safety not established; use only if benefits outweigh risks
Lactation Safety
- Use with caution; excretion in breast milk unknown
Drug Interactions
- Thiazide diuretics (increase risk of hypercalcemia)
- Digoxin (may increase serum levels of digoxin)
Overdose Symptoms
- Severe hypercalcemia
- Renal impairment
Antidote for Overdose
- Discontinue alfacalcidol, provide supportive treatment, and monitor for complications
Storage Conditions
- Store at room temperature away from moisture and heat
Pharmacokinetics
- Absorption: Well absorbed from the intestine
- Distribution: Mainly distributed in the bone and plasma
- Metabolism: Converted to calcitriol in the liver
- Excretion: Primarily excreted in the bile
Precautions
- Monitor serum calcium levels regularly during treatment
- Use with caution in patients with renal impairment
Warnings
- Alfacalcidol can cause hypercalcemia, monitor patients for signs and symptoms