Editor—We have recently seen a child who was prescribed supplements of One-Alpha vitamin D (alfacalcidol; Leo, Princes Risborough, Buckinghamshire) and a calcium supplement as a preventive measure against osteopenia in the treatment of her juvenile polyarthritis. The dose recommended by her paediatrician was 40 ng/kg, a total daily dose of 800 ng.
The child presented with polyuria and a suspected urinary infection. An ultrasound scan of the kidneys showed nephrocalcinosis, and biochemical investigations showed raised concentrations of urea of 9.8 mmol/l, creatinine 120 μmol/l, and calcium 3.68 mmol/l. Creatinine clearance was reduced to 30 ml/mm/1.73m2. The formulation of alfacalcidol was changed in August 2000 so that the original solution had been changed to oral drops with 10 times the concentration of alfacalcidol. Investigation found that the child had been receiving the same volume of the new drop preparation as she had previously been taking of the alfacalcidol solution. Withdrawal of the alfacalcidol preparation and the calcium supplements resulted in a return of her calcium concentrations and renal function to normal after one week.
Other prescribers should be aware of this potentially serious complication of this new high strength formulation, which contains 2 μg/ml, compared with the discontinued solution, which contained only 0.2 μg/ml. If the alfacalcidol solution is prescribed in ml there is a danger of patients receiving 10 times the correct dose.