Increased Calcium Levels and Forteo.

I'll leave others to comment on the calcium question. I chimed in to note that you need to be on a bisphosphonate after Prolia. Forteo is not one of the bisphosphonates. Otherwise you will be at risk of one or more vertebral fractures due to stopping Prolia. Once it is stopped the bone-chewing cells come back with a vengeance and a strong bisphosphonate is needed to hold them in check. Did your doctor discuss this with you or offer an explanation as to why Forteo at this time? Reclast is often the bisphosphonate of choice in your situation, though others take Fosamax. I think two are most commonly used bisphosphonates in this situation.

Hi @sbax75 according to Eli Lilly, "FORTEO has not been studied in patients with pre-existing hypercalcemia. FORTEO may cause hypercalcemia and may exacerbate hypercalcemia in patients with pre-existing hypercalcemia [see Adverse Reactions (6.1, 6.3)]. Avoid FORTEO in patients known to have an underlying hypercalcemic disorder, such as primary hyperparathyroidism." I'm sure your prescribing physician is aware of this precaution.

The manufacture detailed serum calcium concentration changes as follows:
"Serum Calcium Concentrations — When teriparatide 20 mcg was administered once daily, the serum calcium concentration increased transiently, beginning approximately 2 hours after dosing and reaching a maximum concentration between 4 and 6 hours (median increase, 0.4 mg/dL). The serum calcium concentration began to decline approximately 6 hours after dosing and returned to baseline by 16 to 24 hours after each dose"

A clinical study was done regarding serum calcium change:
"the median peak serum calcium concentration measured 4 to 6 hours after dosing with FORTEO (20 mcg subcutaneous once daily) was 9.68 mg/dL at 12 months. The peak serum calcium remained below 11 mg/dL in >99% of women at each visit. Sustained hypercalcemia was not observed. In this study, 11.1% of women treated with FORTEO had at least 1 serum calcium value above the upper limit of normal(ULN) (10.6 mg/dL) compared with 1.5% of women treated with placebo. The percentage of women treated with FORTEO whose serum calcium was above the ULN on consecutive 4- to 6-hour post-dose measurements was 3% compared with 0.2% of women treated with placebo. In these women, calcium supplements and/or FORTEO doses were reduced. The timing of these dose reductions was at the discretion of the investigator. FORTEO dose adjustments were made at varying intervals after the first observation of increased serum calcium (median 21 weeks). During these intervals, there was no evidence of progressive increases in serum calcium."

Hypercalcemia greater than 13mg/dl was reported with Forteo use during postmarketing experience per Eli Lilly.

I had 2 readings of high serum calcium at 10.4 and 10.5mg/dl during early months of Forteo therapy. Nothing was modified but my endo and pcp both kept an eye on the labs. As far as BUN (blood urea nitrogen) goes, mine were as high as 25 to low 30's at times. I've asked ordering physicians about it, none of them were alarmed as my eGFR were perfect. The docs told me if one is dehydrated, the BUN could be easily off the charts.

Hope the above info helps somewhat

This is very helpful information. You sure understand the "drill." Much appreciation for your time and care.
Suzanne