Introduction: Zoledronic acid (ZA) is a bisphosphonate with high antiresorptive potency. Association of ZA with severe acute kidney injury (AKI) has been reported, albeit rare, and predisposing factors include pre-existing renal insufficiency, dehydration and concomitant use of nephrotoxic agents.
Methods: We present a case of severe AKI secondary to toxic acute tubular necrosis (ATN) following treatment with ZA for osteoporosis.
Results: A 70-year-old lady received her first ZA infusion for osteoporosis which was diagnosed after sustaining minimal trauma rib fractures. She had stage 3 chronic kidney disease secondary to diabetic nephropathy. She saw her general practitioner one week after her ZA infusion due to persistent myalgia which started one day after receiving ZA. Blood tests arranged by her GP showed AKI, with a rise in serum creatinine from a baseline of 100μmol/L to 700μmol/L. She was subsequently hospitalised. Apart from ZA, there were no new medications. There was no prior intravenous contrast material exposure. Infection was excluded. Her creatinine peaked at 1,165μmol/L. Her admission was complicated by anuria and fluid overload requiring renal replacement therapy (RRT). A kidney biopsy revealed ATN with mild acute interstitial nephritis (AIN). The close temporal relationship between ZA administration and the onset of AKI strongly implicated ZA as the causative agent in the development of ATN. She was treated with tapering course of prednisolone for AIN. Her renal function gradually improved, with a creatinine of 260μmol/L on hospital discharge. Further RRT was not required. ZA was permanently discontinued. At 4 weeks post-hospital discharge, her creatinine was 140μmol/L and had remained stable.
Conclusion: ZA provides substantial clinical benefits for patients with osteoporosis and has an established safety profile when used appropriately. Appropriate selection of patients and patient monitoring by clinicians can reduce the risk of ZA-associated adverse effects and help ensure the safe use of ZA.