Use of pamidronate in chronic and acute bone loss conditions

Involutional osteoporosis (OP), Osteogenesis imperfecta (OI) and Reflex sympathetic dystrophy syndrome (RSDS) are conditions in which an increase in bone resorption has been described. It therefore seems logical to prescribe a potent inhibitor of bone resorption like pamidronate (APD) in a patient suffering from any of these conditions. In our experience, oral as well as intravenous APD therapy was able to increase significantly bone mineral density (BMD) in patients with OP. This increase was more marked at the lumbar spine than at the proximal femur. With cyclical intermittent APD therapy, a plateauing effect in the BMD results during the third year appeared. After weaning from APD therapy, a remanent effect was observed: no loss of bone apparently occurred for at least two years, but the biological remodeling parameters re-increased earlier. The protective action on OP fractures has still to be clearly demonstrated, however. In children with OI, oral APD therapy has produced a dramatic increase in bone mass, without adversely interfering with the growth spur. The effect on fracture rate is still debatable in such a protean condition. Intravenous APD administered daily for twelve days has provoked a dramatic improvement in patients with long lasting RSDS which had resisted to various well-accepted therapies. However, this was an open trial, and these favorable preliminary results should be confirmed in a double-blind study.