Strontium and Renal Impairment

Is it safe to take strontium for osteoporosis when a patient has reduced kidney function? This question came up recently in a health forum. The patient had been taking strontium citrate for four years, but recently, her eGFR (estimated glomerular filtration rate) had decreased to 49 ml/min, which is considered a moderate decrease in GFR. She was wondering if she could continue taking strontium citrate.

Unfortunately, there are no data relating directly to strontium citrate and reduced kidney function. However, because strontium citrate and strontium ranelate are strontium salts and share some characteristics, we can look at the summary of product characteristics (SPC) for Protelos (strontium ranelate) to arrive at a reasonable answer for strontium citrate. That SPC states that strontium ranelate is not recommended for patients with severe renal impairment (creatinine clearance below 30 ml/min). No dose adjustment is required in patients with mild-to-moderate renal impairment (30-70 ml/min creatinine clearance).

http://www.servier.com/sites/default/files/ProtelosSPCApril2014.pdf

The National Kidney Foundation states normal values for eGFR are 90-120 ml/min. An eGFR below 60 ml/min suggests that some kidney damage has occurred. For information on the eGFR, see:

http://labtestsonline.org/understanding/analytes/gfr/tab/test/