Treatment with glucocorticoids (GCs) is associated with bone loss initiated already early in therapy, causing increased (vertebral) fracture risk. Bone loss is caused by inhibition of bone formation by GCs. Active vitamin D analogues like alfacalcidol directly stimulate osteoblasts leading to an increase in bone formation. Bisphosphonates like alendronate induce apoptosis of osteoclasts leading to inhibition of bone resorption.