Alphacalcidol and renal function in normal subjects.

Sixteen young healthy adults were treated for 3 weeks with alphacalcidol (1 alpha OHD3), 1 microgram orally per day, and renal function tests were performed before, at the end and 3 weeks after termination of the drug. No significant changes occurred in the serum concentrations of calcium or phosphate, whereas the serum calcium-phosphorus product and the urinary excretion of calcium increased significantly. Serum creatinine and the urinary excretion of creatinine showed no significant changes. Inulin clearance decreased by 4% (p = 0.11). The total plasma clearance rate of 51Cr-EDTA and the 24-hour endogenous creatinine clearance both decreased by 4% during the treatment (p less than 0.05). It is concluded that treatment of normal subjects with 1 alpha OHD3, in a modest dose causing no significant change in serum calcium, is associated with a small but reversible decrease in renal function.