Combined Administration of Teripapartide and Antiresorptive Agents in Postmenopausal Osteoporosis

Inclusion Criteria: * Ambulatory postmenopausal women at least 55 years of age * Patients with "unsatisfactory clinical response to previous antiresorptive therapy" according to the national reimbursement criteria of Austria (either new clinical or radiographic fragility fracture on ≥ 2 years and/or accelerated bone loss of ≥ 3.5%/year on antiresorptive treatment; discontinuation of oral antiresorptive treatment due to side-effects and substantial risk for osteoporotic fracture defined by a T-Score ≤ -2.5 or ≥ 2 clinical risk factors according to the FRAX™-algorithm)and consequently started with teriparatide treatment * Patients treated with teriparatide (20 ug/day) currently and since 9 months for postmenopausal osteoporosis * Lumbar spine, femoral neck, and total hip evaluable by dual energy x ray absorptiometry (DXA) * Normal or clinically non-significant abnormal laboratory values (as defined by the investigator) * Without language barrier, cooperative, expected to return for all follow-up procedures, and who give informed consent before entering the study and after being informed of the medications and procedures to be used in this study Exclusion Criteria: * History of bone metabolic diseases, Paget's disease, renal osteodystrophy, osteomalacia, any secondary causes of osteoporosis, hyperparathyroidism (uncorrected), and intestinal malabsorption * History of malignant neoplasms in the prior 5 years, with the exception of superficial basal cell carcinoma or squamous cell carcinoma of the skin that has been definitively treated. If malignant neoplasm was ever diagnosed, patient must presently be free of disease * History of nephrolithiasis or urolithiasis in the prior 2 years. Patients with any documented history of nephro- or uro-lithiasis must have had an appropriate imaging procedure within the prior 6 months, such as, an intravenous pyleogram (IVP), supine radiograph of the kidney ureter bladder, or renal ultrasound, which must document the absence of stones * Abnormal thyroid function at any time in the prior 6 months. Patients with chronic hypothyreosis and adequate substitution therapy are permitted * Active liver disease (liver enzymes more than three times the upper limit of normal) or clinical jaundice * Significantly impaired renal function. This is defined as serum creatinine \>1.8 mg/dL * Treatment with bone active agent other than teriparatide in the prior 9 months