One drug class, two very different kidney lesions
Bisphosphonate nephrotoxicity
The intravenous bisphosphonates that protect bone in myeloma and metastatic cancer split the nephron between them — pamidronate poisons the podocyte and produces a collapsing FSGS with nephrotic-range proteinuria, while zoledronate poisons the proximal tubule and produces a toxic ATN — and both are dose- and infusion-rate-dependent, so the same monitoring that catches them also prevents them.
- 12.4 g/day
- proteinuria (pamidronate FSGS)Mean 24-hour urinary protein in the 7 patients whose collapsing FSGS was first linked to a drug — pamidronate, at escalated doses; mean serum creatinine 3.6 mg/dL
- 1.4 → 3.4
- creatinine (zoledronate ATN)Mean serum creatinine (mg/dL) in the first zoledronate toxic-ATN series of 6 patients on the standard 4-mg dose — partially reversible after the drug was stopped
- ~20%
- SCr rise at 12 monthsClinically relevant serum-creatinine increase by month 12 in the standard 15-minute-infusion arm of the 176-patient ZMAX zoledronic-acid trial (~28% by 24 months; the 30-minute arm was similar at 16% / 27%)
- first
- drug ever linked to collapsing FSGSBefore pamidronate, the only epidemiologic factor tied to collapsing FSGS was HIV — this was the first association of the lesion with a therapeutic agent
- dose + infusion
- the two determinantsIV bisphosphonate nephrotoxicity is both dose-dependent and infusion-time-dependent, so pre-dose creatinine checks, withholding in renal insufficiency, and CKD dose-adjustment largely prevent it
Teaching case · illustrative composite, not a real patient
A 61-year-old man with multiple myeloma has been on monthly intravenous pamidronate for nearly three years, with the dose escalated above the standard 90 mg for persistent bone pain. He develops progressive lower-extremity edema; labs show a serum creatinine risen from a normal baseline to 3.4 mg/dL and 11 grams of proteinuria per day with hypoalbuminemia.
The nephrotic-range proteinuria and rising creatinine in a patient on long-term, dose-escalated pamidronate raise collapsing focal segmental glomerulosclerosis. A kidney biopsy confirms it. Pamidronate is stopped, the nephrotic syndrome is managed supportively, and — because bone protection is still needed — therapy is switched away from pamidronate, with close monitoring of renal function and proteinuria. Had this instead been a patient on zoledronate presenting with a rising creatinine and a bland urine, the lesion to expect would be toxic acute tubular necrosis, which more often recovers partially once the drug is withdrawn.
Teaching point — Intravenous bisphosphonate nephrotoxicity is really two syndromes: pamidronate is toxic to the podocyte and causes collapsing FSGS with heavy proteinuria (often at escalated doses, over months to years), while zoledronate is toxic to the proximal tubule and causes ATN with a rising creatinine and a bland sediment (at the standard dose, over months, more often reversible). A biopsy distinguishes them. Both are dose- and infusion-rate-dependent — which is why oral bisphosphonates and low-dose osteoporosis regimens are essentially not nephrotoxic, and why checking creatinine before each dose, withholding for renal insufficiency, and never shortening the infusion are the whole prevention strategy. Ibandronate has a comparatively safe renal profile.
How it happens
The pathophysiology as a cascade — select a step to follow the mechanism.
How we learned it
- 2001
Markowitz and colleagues report 7 patients — older, HIV-negative — who developed collapsing FSGS with nephrotic syndrome (mean proteinuria 12.4 g/day) during cancer treatment, the only common agent being pamidronate at escalated doses.
The first association of collapsing FSGS with any therapeutic agent, until then tied only to HIV — and the discovery of pamidronate's podocyte toxicity.
PMID 11373339 - 2003
Markowitz and colleagues describe the first series of zoledronate nephrotoxicity — 6 patients on the standard 4-mg dose who developed toxic ATN (creatinine 1.4 → 3.4 mg/dL), a distinct lesion with no collapsing FSGS even in those previously exposed to pamidronate.
Showed that a second bisphosphonate injures a different part of the nephron — the tubule, not the podocyte — establishing the two-lesion picture.
PMID 12787420 - 2008
Perazella and Markowitz synthesize the field: IV bisphosphonate nephrotoxicity is both dose- and infusion-time-dependent, largely preventable by creatinine monitoring and dose adjustment, and much less of a problem for the oral drugs and low-dose osteoporosis regimens.
The reference review — pairing each agent to its lesion and codifying the monitoring that prevents severe injury.
PMID 18685574 - 2011
The ZMAX trial randomizes 176 myeloma patients to 15- versus 30-minute zoledronic-acid infusions: a clinically relevant creatinine rise occurred in ~20% of the standard 15-minute arm by 12 months (~28% by 24 months), with the 30-minute arm no better (16% / 27%).
Quantified the everyday renal signal of standard zoledronic acid and defined 15 minutes as the practical infusion floor.
PMID 21465735
The landmark studies
Collapsing focal segmental glomerulosclerosis following treatment with high-dose pamidronate
Markowitz GS, et al. · J Am Soc Nephrol 2001 · PMID 11373339
Pamidronate — the only agent common to all 7 — caused collapsing FSGS with nephrotic syndrome, the first time the lesion was linked to a drug rather than to HIV.
7 patients; doses escalated to 180 mg (2) and 360 mg (3) monthly; 15–48 months to presentation; mean creatinine 3.6 mg/dL; mean proteinuria 12.4 g/day
Toxic acute tubular necrosis following treatment with zoledronate (Zometa)
Markowitz GS, et al. · Kidney Int 2003 · PMID 12787420
Standard-dose zoledronate caused toxic ATN — tubular degeneration, brush-border loss, apoptosis — distinct from pamidronate's collapsing FSGS, and partially reversible after withdrawal.
6 patients; zoledronate 4 mg monthly over ≥15 min; mean 4.7 months of therapy; creatinine 1.4 → 3.4 mg/dL; partial recovery to 2.3 mg/dL after stopping
Bisphosphonate nephrotoxicity
Perazella MA, Markowitz GS · Kidney Int 2008 · PMID 18685574
IV bisphosphonate nephrotoxicity is dose- and infusion-time-dependent, agent-specific in its lesion (ATN for zoledronate, collapsing FSGS for pamidronate), and largely preventable with monitoring; ibandronate has a safe renal profile.
Oral bisphosphonates: not significantly nephrotoxic; ibandronate safe even with abnormal baseline function; prevention = pre-dose creatinine, withhold for renal insufficiency, CKD dose-adjust
Infusion duration of zoledronic acid in multiple myeloma (the ZMAX trial)
Berenson JR, et al. · J Support Oncol 2011 · PMID 21465735
Standard zoledronic acid caused a clinically relevant creatinine rise in a meaningful minority, and lengthening the infusion from 15 to 30 minutes did not further reduce that risk.
SCr rise 20% (15-min) vs 16% (30-min) at 12 mo (P=0.44); 28% vs 27% at 24 mo (P=0.90); peak concentration 249 vs 172 ng/mL
What the data says now
How disproportionately each agent's FAERS reports name these phenotypes vs. all other drugs (reporting odds ratio; significant signals only, 95% CI lower bound > 1; as of 2026-07-10). A reporting signal, not incidence or proven causation.
| Agent | GLOM | ATN | LYTE |
|---|---|---|---|
| Pamidronate | Pamidronate, Glomerular Injury / Proteinuria: ROR 10.44, 48 reports | Pamidronate, Acute Tubular Necrosis: ROR 5.73, 9 reports | Pamidronate, Electrolyte Disturbance: ROR 6.32, 185 reports |
Proteinuria (pamidronate collapsing FSGS)
7-patient collapsing-FSGS series, mean 24-hour protein
PMID 11373339Creatinine at presentation (pamidronate FSGS)
Same 7-patient series, mean at presentation
PMID 11373339Creatinine rise (zoledronate ATN)
6-patient toxic-ATN series, standard 4-mg dose
PMID 12787420Clinically relevant SCr rise at 12 months
Standard 15-minute-infusion arm (~88 patients) of the 176-patient ZMAX trial
PMID 21465735How it's managed
- 1
Check serum creatinine before every dose
Measure serum creatinine before each IV bisphosphonate dose and withhold therapy in the setting of renal insufficiency until it recovers. This single habit is what turns a potentially severe nephrotoxicity into a preventable one.
Definitive review — monitoring and withholding largely prevent severe injury · PMID 18685574
- 2
Respect the dose and the infusion time
Use the approved dose and infusion duration — do not escalate the dose or shorten the infusion, since both drive the injury. The ZMAX trial found 15- and 30-minute zoledronic-acid infusions comparable, so ≥15 minutes is the practical floor rather than the faster the better.
Infusion-duration RCT — 15 vs 30 min comparable; ≥15 min floor · PMID 21465735
- 3
Match the lesion to the drug
Nephrotic-range proteinuria on pamidronate points to collapsing FSGS; a rising creatinine with a bland sediment on zoledronate points to toxic ATN. Stop the culprit agent — the ATN often recovers partially, whereas the collapsing FSGS may not — and biopsy when the picture is unclear.
First zoledronate ATN series — distinct, partially reversible lesion · PMID 12787420
- 4
For CKD or prior toxicity, adjust or switch
Dose-adjust in pre-existing CKD, and where renal risk is high consider ibandronate (a comparatively safe renal profile even with abnormal baseline function) or the non-bisphosphonate denosumab — watching for hypocalcemia at low GFR with the latter.
Review — ibandronate renal safety; agent selection in CKD · PMID 18685574
What the guidelines say
Society and consensus recommendations addressing this syndrome, each with its key recommendation quoted verbatim.
Every citation on this page is a real, PubMed-verified reference. The teaching case is an illustrative composite, not a real patient. Medical-education content — not medical advice.