Alfacalcidol
Indications
Alfacalcidol is used for:
Hypoparathyroidism, Hypocalcaemia, Renal osteodystrophy, Hypophosphataemia, Rickets or osteomalacia
Adult Dose
Adult: PO Hypocalcaemia; Hypoparathyroidism; Hypophosphataemia; Renal osteodystrophy; Rickets or osteomalacia Initial: 1 mcg/day. Maintenance: 0.25-1 mcg/day.
Elderly: 0.5 mcg daily.
Child Dose
Child: PO: Premature infants and neonates: 0.05-0.1 mcg/kg daily; <20 kg: 0.05 mcg/kg daily.
Renal Dose
Administration
Administration Should be taken with food.
Contra Indications
Hypercalcaemia, metastatic calcification, hyperphosphataemia (except when occurring with hypoparathyroidism), hypermagnesaemia.
Precautions
Pregnancy, lactation, renal impairment, infants, elderly. Monitor serum levels of calcium in patients with renal failure. Caution in hypercalciuria esp in those with history of renal calculi. Avoid in patients with hypersensitivity to inj. containing propylene glycol.
Pregnancy-Lactation
Interactions
Thiazides may increase the risk of hypercalcaemia. Some antiepileptics e.g. carbamazepine, phenobarbital, phenytoin and primidone may increase vitamin D requirements. Rifampicin, isoniazid and corticosteroids may reduce the efficacy of vitamin D.
Adverse Effects
Side effects of Alfacalcidol :
Anorexia, nausea, vomiting, diarrhoea, lassitude, polyuria, sweating, headache, thirst, vertigo, pruritus, rash, urticaria. Hypercalcaemia, hypercalciuria and ectopic calcification.
In case of renal impairment, hyperphosphataemia. In hypercalcaemic dialysis patients, possibility of calcium influx from the dialysate should be considered.
Mechanism of Action
Alfacalcidol is a precursor of the active calcitriol. It does not require renal hydroxylation but requires 25-hydroxylation in the liver for conversion to calcitriol.