LONG-TERM EFFECTS OF SMALL DOSES OF 1,25-DIHYDROXYCHOLECALCIFEROL IN RENAL OSTEODYSTROPHY

An oral dose of 0.5 .mu.g of 1,25-dihydroxycholecalciferol (1,25-[OH]2D3) and 4 g of calcium carbonate was given daily to 2 dialyzed patients and 3 undialyzed patients in chronic renal failure with renal osteodystrophy. Treatment was given for 4-16 mo. Intestinal Ca absorption became normal in all 5 patients. Plasma alkaline phosphatase, hydroxyproline and immunoreactive parathyroid hormone were considerably reduced in all of the patients and in 4 of them these values were restored to normal. Bone histology was improved in all patients after treatment with 1,25-(OH)2D3. As well as a dramatic improvement in bone mineralization, there was remodelling of trabecular architecture and a decrease in fibrosis in patients with initial parathyroid overactivity.