To minimize the risk of chronic kidney disease (CKD) progressing to end-stage renal disease (ESRD), such osteoporosis medications as alendronate (Fosamax) and ibandronate (Boniva) are contraindicated in individuals whose glomerular filtration rate (GFR) is <30%. But is it safe to restart these medications once stage 5 CKD (or dialysis) has been reached? — Jason Tiede, PA, Edmond, Okla.

The FDA currently warns against using bisphosphonates in patients with GFR <30 mL/min/1.73 m2, which includes patients with stage 3, 4 or 5 CKD. This warning is based on studies with rats that were given rapid high doses of the drug, which resulted in histologic changes and acute kidney injury.

Several subsequent large trials suggest that in the absence of secondary causes of low bone mineral density (BMD), use of recommended doses of bisphosphonates in patients with age-related stage 2, 3 or 4 CKD may not be as nephrotoxic as believed. Additionally, a large trial using ibandronate in dialysis patients (stage 5) showed a significant improvement in BMD.

A smaller study evaluating alendronate in dialysis patients resulted in stabilization of hip density in subjects taking alendronate, while subjects on placebo showed worsening of BMD. However, current FDA recommendations have not been revised. For a detailed summary of the latest evidence regarding this unsettled topic, see Am J Kidney Dis. 2010;55:941-956. — Claire Babcock O’Connell, MPH, PA-C (159-5)