Abstract

Osteoporosis is a rare but potentially severe complication under high-dose, long-term unfractionated heparin therapy. The mechanisms by which unfractionated heparins cause increased bone resorption in humans are unknown. Low molecular weight heparins have gained increased importance in antithrombotic therapy over the last decade. Whether this heterogeneous group of drugs carries a comparable risk of osteoporosis in long-term application is unknown. In a standardised in vitro model the effects of four different low molecular weight heparins on osteoblast growth were studied. In comparison to control groups low molecular weight heparins caused a significant inhibition of osteoblast growth. Therefore, the risk of osteoporosis under long-term therapy with high doses of low molecular weight heparins cannot be excluded and should be further evaluated in clinical trials.