Effects of Zoledronic Acid Versus Alendronate on Bone Loss After Kidney and Kidney/Pancreas Transplants

Inclusion Criteria: * Transplant patients who have had a kidney or kidney/pancreas transplant in the last 150 days with adequate kidney function as defined by a calculated creatine clearance of 35ml/min or more and serum creatinine less than 3.0 Exclusion Criteria: * Dual X-ray Absorptiometry (DXA) T-score at the spine or hip of -3 or lower * History of more than one vertebral or non-vertebral fracture in the past two years * Abnormalities of the esophagus which delay esophageal emptying * Inability to stay upright for 30 minutes * Pregnant, nursing women or women not using an effective form of birth control * Hypocalcemia * Hypercalcemia * Calculated creatinine clearance of \<35 ml/min or serum creatinine \> 3.0 * Patients already treated with bisphosphonates within the past one year * Patients unable to undergo DXA * Patients with cancer