PRESCRIBED FOR: Injectable calcitonin is used to treat osteoporosis and Paget's disease. Injectable calcitonin also is used to treat seriously elevated blood calcium levels. The nasal spray is used only for osteoporosis in women who are at least 5 years postmenopausal. DOSING: Injectable calcitonin is injected under the skin or into the muscle. The nasal spray is administered into the nostril. To achieve optimal results, patients with osteoporosis should simultaneously receive adequate amounts of calcium and vitamin D.