An apparent 1,25-dihydroxyvitamin D-independent stimulation of intestinal calcium absorption in patients with Paget disease of bone during a short-term diphosphonate therapy.

Six patients with Paget disease of bone were treated with a 6-mo course of disodium-ethane-1-hydroxy-1, 1-diphosphate (EHDP) at a dosage of 5 mg/kg/day (one patient) or 20 mg/kg/day (five patients). In addition to symptomatic and biochemical improvement which persisted 3 mo after discontinuance of therapy, EHDP resulted in a significant increase in intestinal calcium absorption that was not correlated with a change in serum 1 alpha, 25-(OH)2-vitamin D concentration. EHDP appears to stimulate intestinal calcium transport by either a vitamin D independent process or by an increased intestinal mucosal cell sensitivity to vitamin D.