Check out the thread about Quitting Prolia. Once you stop Prolia you need to be checking your CTX. It is important to check it before you start any treatment really. I quit taking Prolia after my 5th injection. I wanted to do it sooner , but was unable to find someone qualified to assist me. I started Alendronate under the direction of my physician 15 days after my scheduled Prolia shot. I did a CTX test. The next day I started the Alendronate. I will be monitoring my CTX every 3 months to monitor where that marker is. I am hoping it will stay under 212.Iif it does not I will need to have a Reclast infusion and continue to watch. The research is not clear about how long the rebound can continue. Monitoring needs to continue for a minimum of a year. Hopefully, this is helpful.