CYCLICAL PAMIDRONATE INFUSIONS IN POSTMENOPAUSAL OSTEOPOROSIS

Objectives: Until recently, two bisphosphonates, pamidronate (APD) and etidronate were available for clinical purposes. Contrary to etidrona te, pamidronate was not extensively studied in osteoporosis. Therefore , we investigated the effect of cyclic intravenous APD treatment in po stmenopausal osteoporosis. Methods: Parameters of bone remodelling and lumbar spine bone mineral density (BMDL) were assessed in 36 postmeno pausal women with osteoporosis (BMDL r-score < -2.5). They received fi ve courses of APD. Intervals between courses were defined according to the fasting urinary calcium excretion (UCa/Cr, mg/mg creatinine) whic h was measured before each APD course and every 2 weeks after the firs t treatment. The patients were retreated when UCa/Cr had reached basel ine levels. Serum biochemical parameters and urinary hydroxyproline (U OHPro/Cr, mg/mg) were measured before each APD. Results: UCa/Cr decrea sed during 21-28 days after each course but UCa/Cr measured before APD infusion remained unchanged. UOHPro/Cr significantly fell after the t hird APD (P = 0.02). Serum calcium was however not modified. Parameter s of bone remodelling decreased with time: bone-GLA protein (BGP) star ted to fall after the first APD (P 0.0001) and continued to decrease u ntil the fourth APD course, alkaline phosphatase (ALP) significantly d ecreased after the first APD (P = 0.005); intact PTH significantly inc reased at the fifth APD (P = 0.02). BMDL significantly increased after 1 year treatment: +2.9% of baseline value. Conclusions: Cyclical pami dronate treatment of postmenopausal osteoprosis appeared to be effecti ve in reducing bone turnover assessed by BGP, ALP and OHPro/Cr. This e ffect is followed by an increase in vertebral BMD.