@normahorn great question about the testing protocol for the switch from Prolia to Reclast. The standard timing is 6 months but both Keith McCormick and my doctor say it is trickier than that, as was discussed above.

From McCormick's book "Great Bones": he recommends CTX assays at 4-6 week intervals. That is the only way, he says, to assess whether and when the effects of Prolia have worn off. If the CTX remains steadily low, the Prolia is still working. Reclast would not work if Prolia is still active, but if Reclast is too late, bone loss might already occur. You do Reclast whe CTX levels rise.

Of course it can take 2-4 weeks to schedule the infusion, which is a problem!

He further says have another CTX test one month after Reckast and again 3-6 months later. If CTX levels continue to rise, another Reclast infusion might be needed. He says that sometimes there is an initial beneficial lowering of CTX the first month after Reclast and then a "dramatic rise" 3 months later, "indicating rapid bone loss." Hence a need for another infusion. "The key to successful transition is to do multiple CTX assays." pg 449-450