Forteo use for more than 2 years total is not recommended.
In animal studies, some rats who were treated with Forteo developed osteosarcoma (a form of bone cancer). An increased risk of osteosarcoma hasn’t been found in human studies. However, in these studies, the drug was only used for up to 2 years. So it isn’t known if Forteo could increase the risk of osteosarcoma after 2 years of treatment.
It’s best to talk with your doctor about other options to treat your osteoporosis after 2 years of treatment with Forteo. Your doctor can give you more information on whether the benefits of continued Forteo treatment outweigh your risks for developing osteosarcoma.