Drug-induced kidney injury compared — hemodynamic, tubular, interstitial and crystal injury
Verified · Oct 2026Drugs injure the kidney in a few repeatable ways: they lower glomerular filtration, poison the proximal tubule, provoke interstitial inflammation, or precipitate as crystals. Knowing the pattern tells you the clue to look for and how to prevent it.
Four ways drugs injure the kidney
Drug toxicity accounts for about 20% of renal injury, and the largest share of the people affected are over 70. The common mechanisms are few. GFR alteration: ACE inhibitors, ARBs, NSAIDs, cyclosporine and tacrolimus change intraglomerular hemodynamics. Tubular cell toxicity: aminoglycosides, amphotericin B, cisplatin, adefovir and foscarnet damage proximal tubular cells through free radicals, mitochondrial damage and injury to transport systems. Interstitial nephritis: NSAIDs and rifampin are common acute causes, while analgesics, anticancer drugs, lithium and calcineurin inhibitors cause chronic forms. Crystal nephropathy: drugs that are poorly soluble in urine, such as acyclovir and ampicillin, precipitate in the distal tubular lumen, obstructing and injuring the tubule.
The glomerular hemodynamics explain the first group. Prostaglandins E2 and I2 normally dilate the afferent arteriole, so NSAIDs constrict it and lower filtration; angiotensin II maintains filtration by acting on the efferent arteriole, so ACE inhibitors and ARBs lower intraglomerular pressure. Renal toxicity follows when renal prostaglandins have a compensatory role in maintaining perfusion, or when renal function depends on the renin–angiotensin system — as in renal artery stenosis, chronic kidney disease, severe heart failure or volume depletion.
Prevention follows the mechanism
Baseline renal function is determined before and after a nephrotoxic drug is started. Combinations add risk: the “triple whammy” of an ACE inhibitor or ARB, a diuretic and an NSAID increases the risk of acute kidney injury, and nephrotoxic drugs such as NSAIDs, cyclosporine and diuretics add to the risk with aminoglycosides.
Hydration protects against several of these drugs. Dehydration raises the risk of aminoglycoside toxicity; IV acyclovir must be given with adequate hydration and over at least 1 hour; the cisplatin label requires adequate hydration; pretreatment with normal saline can attenuate amphotericin B nephrotoxicity; and periprocedural IV normal saline is the common strategy against contrast-induced nephropathy, together with using less contrast and a low- or iso-osmolar agent.
Comparison
Drug by drug
| Drug | Pattern of injury | Mechanism | Clue and monitoring |
|---|---|---|---|
| NSAIDs | Lowered GFR; acute interstitial nephritis (the most common cause, 44% of cases); chronic interstitial injury (analgesics) | Inhibit renal prostaglandins that dilate the afferent arteriole | Acute renal failure is dose- and duration-dependent and reversible; hyperkalemia; nephrotic-range proteinuria in NSAID interstitial nephritis |
| ACE inhibitors | Lowered GFR (hemodynamic) | Loss of efferent arteriolar tone lowers intraglomerular pressure | A creatinine rise up to 30% is expected; more than 30% → look for bilateral renal artery stenosis or volume depletion |
| ARBs | Lowered GFR (hemodynamic) | Lower intraglomerular pressure | Acute renal failure especially with renal artery stenosis, chronic kidney disease, severe heart failure or volume depletion |
| Loop diuretics | Prerenal (volume depletion) | Excessive diuresis lowers renal blood flow and GFR | Azotemia; orthostatic hypotension |
| Aminoglycosides | Proximal tubular cell toxicity | Accumulate in proximal tubular cells | Up to 10–25% of patients, generally reversible; urine with decreased specific gravity, protein, cells or casts; periodic BUN and creatinine |
| Amphotericin B | Proximal tubular cell toxicity | Damages proximal tubular cells | Hypokalemia, hypomagnesemia; saline pretreatment attenuates it; lipid formulations are less nephrotoxic |
| Cisplatin | Proximal tubular cell toxicity | Damages proximal tubular cells | Boxed nephrotoxicity, dose-related and cumulative; hydration; monitor renal function and electrolytes |
| Tenofovir | Renal impairment, including Fanconi syndrome | — | Serum creatinine, creatinine clearance, urine glucose and urine protein before and during use |
| Acyclovir (IV) | Crystal nephropathy | Crystals form in the renal tubules | Infuse over at least 1 hour with adequate hydration; dehydration, renal disease and other nephrotoxins raise the risk |
| Penicillins | Acute interstitial nephritis; crystals (ampicillin) | Inflammation of the tubules and interstitium | Fever, rash and eosinophilia (classic with methicillin); nafcillin: hematuria, proteinuria, AKI — most resolve when it is stopped |
| Sulfonamides (TMP-SMX) | Acute interstitial nephritis; crystal nephropathy | Poor urinary solubility (sulfonamides) | Ensure adequate fluid intake and urine output; trimethoprim blocks ENaC, causing hyperkalemia |
| Lithium | Nephrogenic diabetes insipidus; chronic tubulointerstitial nephropathy | Reduced renal concentrating ability | Polyuria and polydipsia; kidney function tests before starting and once or twice a year; NSAIDs, thiazides, ACE inhibitors and ARBs raise lithium levels |
| Heroin | Rhabdomyolysis; renal failure | Chronic or high-dose exposure; prolonged immobilization | Creatine phosphokinase to exclude rhabdomyolysis; creatinine and electrolytes |
| Iodinated contrast | Contrast-induced nephropathy | Direct proximal tubular cytotoxicity, reactive oxygen species and medullary vasoconstriction | Creatinine rises within 24 hours, peaks at 3–5 days and returns to baseline in 7–10 days; mostly nonoliguric |
| Gadolinium (MRI contrast) | Not a direct kidney injury: nephrogenic systemic fibrosis in low GFR | Linear agents bind gadolinium less tightly and carry more risk | Acute or severe chronic renal failure, usually stage 4–5 CKD; boxed warning in severely decreased GFR |
— = not stated on the source pages.
Pattern by pattern
| Pattern | Drugs | What points to it |
|---|---|---|
| Lowered GFR (hemodynamic or prerenal) | NSAIDs, ACE inhibitors, ARBs; overdiuresis with loop diuretics | Renal perfusion that depends on prostaglandins or angiotensin II; volume depletion |
| Proximal tubular cell toxicity | Aminoglycosides, amphotericin B, cisplatin, iodinated contrast | Urine casts and cells (aminoglycosides); timing after contrast |
| Acute interstitial nephritis | NSAIDs (44%); antibiotics including penicillins and sulfonamides (about 33%) | Fever, rash and eosinophilia, most typical with β-lactams; heavy proteinuria with NSAIDs |
| Crystal nephropathy | Acyclovir, sulfonamides, ampicillin | Poorly soluble drug precipitating in the distal tubular lumen |
| Concentrating defect and chronic interstitial injury | Lithium | Polyuria and polydipsia; chronic injury with prolonged use |
| Rhabdomyolysis | Heroin | Prolonged immobilization; raised creatine phosphokinase |
High-yield
Practice questions
Q1A 79-year-old woman with heart failure takes lisinopril and furosemide. After a week of ibuprofen for knee pain, her creatinine has doubled and her potassium is 5.8 mEq/L. Her creatine kinase is normal.
What best explains her kidney injury?
- A.Crystal precipitation in the distal tubules
- B.Direct toxicity to proximal tubular cells
- C.Nephrogenic diabetes insipidus
- D.Rhabdomyolysis
- E.Reduced glomerular filtration from the combined hemodynamic effects of her drugs
Show answer
E. Reduced glomerular filtration from the combined hemodynamic effects of her drugs — NSAIDs inhibit the renal prostaglandins that dilate the afferent arteriole, ACE inhibitors remove the efferent arteriolar tone that maintains filtration, and the “triple whammy” of an ACE inhibitor or ARB, a diuretic and an NSAID increases the risk of acute kidney injury; hyperkalemia can occur with NSAIDs. Crystal nephropathy comes from poorly soluble drugs such as acyclovir, ampicillin and sulfonamides, and direct proximal tubular toxicity from drugs such as aminoglycosides, amphotericin B and cisplatin. Nephrogenic diabetes insipidus is lithium’s effect, and rhabdomyolysis is excluded by a normal creatine kinase.
Q2A 67-year-old man has received IV gentamicin for 10 days for endocarditis. His creatinine is rising, and his urine shows a low specific gravity, protein and granular casts.
Where does gentamicin injure the kidney?
- A.The afferent arteriole, by blocking prostaglandin-mediated dilation
- B.The interstitium, through a hypersensitivity reaction
- C.The proximal tubular cells, where it accumulates
- D.The collecting duct, by blocking the response to ADH
Show answer
C. The proximal tubular cells, where it accumulates — Gentamicin accumulates in renal proximal tubular cells and damages them; nephrotoxicity appears in up to 10 to 25% of patients, is generally reversible, and is more likely with high or prolonged dosing. The label calls for examining the urine for decreased specific gravity, protein, cells or casts and for periodic BUN and creatinine. Blocking afferent dilation is the NSAID mechanism, a hypersensitivity interstitial nephritis is typical of β-lactams and NSAIDs, and a reduced response to ADH in the collecting duct is lithium’s nephrogenic diabetes insipidus.
Q3Ten days into IV nafcillin for osteomyelitis, a 45-year-old woman develops fever, a rash and eosinophilia, with hematuria, proteinuria and a rising creatinine.
What is the most important first step?
- A.Stop the nafcillin
- B.Switch to ampicillin
- C.Continue nafcillin and start corticosteroids
- D.Continue nafcillin and give IV fluids for a prerenal injury
Show answer
A. Stop the nafcillin — Nafcillin is associated with renal tubular damage and interstitial nephritis, presenting with hematuria, proteinuria and acute kidney injury that may come with rash, fever and eosinophilia; most cases resolve when it is stopped, and withdrawing the offending drug is the mainstay of treatment. Corticosteroids are considered only if renal function has not improved 5 to 7 days after the drug is withdrawn. Ampicillin is another β-lactam — the class most likely to cause this hypersensitivity picture — and fever, rash and eosinophilia point to interstitial nephritis, not a prerenal cause.
Q4A 70-year-old man with stage 4 chronic kidney disease needs contrast imaging, and his team weighs a gadolinium-enhanced MRI against an iodinated-contrast CT.
Which risk is specific to the gadolinium-based agent in him?
- A.A creatinine rise that peaks 3 to 5 days later
- B.Nephrogenic systemic fibrosis
- C.Acute interstitial nephritis
- D.Crystal nephropathy
Show answer
B. Nephrogenic systemic fibrosis — Nephrogenic systemic fibrosis is a progressive multiorgan fibrosing condition caused by gadolinium-based contrast agents in the setting of low GFR, usually stage 4 or 5 chronic kidney disease; linear agents bind gadolinium less tightly and carry more risk, and the FDA placed a boxed warning on gadolinium products in severely decreased GFR. A creatinine rise within 24 hours that peaks at 3 to 5 days is contrast-induced nephropathy from iodinated contrast. Interstitial nephritis is typical of NSAIDs and antibiotics, and crystal nephropathy of poorly soluble drugs such as acyclovir.
Sources
- Nephrotoxic Medications — StatPearls (NCBI)
- Allergic and Drug-Induced Interstitial Nephritis — StatPearls (NCBI)
- Contrast-Induced Nephropathy — StatPearls (NCBI)
- Nephrogenic Systemic Fibrosis — StatPearls (NCBI)
- Heroin Toxicity — StatPearls (NCBI)
- Nonsteroidal Anti-inflammatory Drugs (NSAIDs) — StatPearls (NCBI)
- COX Inhibitors — StatPearls (NCBI)
- Celebrex (celecoxib) — FDA label — FDA / DailyMed
- Physiology, Glomerular Filtration Rate — StatPearls (NCBI)
- Incidence of the Triple Whammy Phenomenon (Front Nephrol 2025) — Frontiers (PMC)
- Antihypertensive Medications — StatPearls (NCBI)
- Prerenal Kidney Failure — StatPearls (NCBI)
- Renal Artery Stenosis — StatPearls (NCBI)
- Angiotensin II Receptor Blockers (ARB) — StatPearls (NCBI)
- Ethacrynic Acid — StatPearls (NCBI)
- Therapeutic Uses of Diuretic Agents — StatPearls (NCBI)
- Aminoglycosides — StatPearls (NCBI)
- Gentamicin — StatPearls (NCBI)
- Gentamicin sulfate injection — FDA label — FDA / DailyMed
- Amphotericin B — StatPearls (NCBI)
- Amphotericin B for injection — FDA label — FDA / DailyMed
- Cisplatin for injection — FDA label — FDA / DailyMed
- Acyclovir injection — FDA label — FDA / DailyMed
- Acyclovir — StatPearls (NCBI)
- Truvada (emtricitabine/tenofovir disoproxil fumarate) — FDA label — FDA / DailyMed
- Viread (tenofovir disoproxil fumarate) — FDA label — FDA / DailyMed
- Nafcillin injection — FDA label — FDA / DailyMed
- Penicillin — StatPearls (NCBI)
- Bactrim (sulfamethoxazole/trimethoprim) — FDA label — FDA / DailyMed
- Hypoaldosteronism — StatPearls (NCBI)
- Trimethoprim-Sulfamethoxazole — StatPearls (NCBI)
- Lithium carbonate — FDA label — FDA / DailyMed
- Nursing: Mental Health and Community Concepts 2e, Ch. 6 Psychotropic Medications — Open RN (NCBI Bookshelf)
- Lithium — StatPearls (NCBI)
- Lithium Toxicity — StatPearls (NCBI)
Each class page compared lists its full sources; this page reuses facts verified there.
By LearnDrugs
Educational summary for medical students. Always verify against current prescribing information and guidelines. Not medical advice.