This has not happened to me, exactly. I was on alendronate for 3.5 years with no improvement, and am now trying Forteo. Sometimes certain meds just don't work for some people, but I don't know how common it is for two different meds to not work. Have you had tests to rule out secondary causes of osteoporosis such as hyperthyroidism,,hyperparathyroidism, celiac disease and Cushing's syndrome? Osteo meds won't help if you do have an underlying, untreated cause.