Why this topic matters: Nephrotoxins are medicines, chemicals or biological substances that injure the kidneys or reduce renal perfusion. Drug-induced kidney injury may be missed because the patient initially feels well and creatinine rises after the exposure. EMTs and emergency staff reduce harm by taking a complete medication and herbal history, checking volume status, identifying high-risk combinations, monitoring urine and electrolytes, stopping avoidable exposure and escalating early.
Learning objectives
- Define nephrotoxicity and explain common mechanisms of kidney injury.
- Recognise patients at increased risk and identify common drug and chemical exposures.
- Perform an emergency assessment for AKI, hyperkalaemia, acidosis, fluid overload and obstruction.
- Describe prevention, dose adjustment, monitoring, decontamination and renal referral.
- Plan nursing interventions, patient education and safe follow-up.
What is nephrotoxicity?
Nephrotoxicity is kidney injury caused by a medicine, toxin or chemical. A substance may directly damage tubular cells, trigger interstitial inflammation, cause glomerular injury, reduce renal blood flow, precipitate crystals or produce obstruction. Injury is more likely when several risks combine: dehydration, sepsis, hypotension, older age, diabetes, CKD, heart failure, pregnancy, high dose, prolonged treatment or multiple nephrotoxic medicines.
Nephrotoxicity may present as rising creatinine, falling urine output, haematuria, proteinuria, electrolyte disturbance, oedema, hypertension, rash or systemic toxicity. It can coexist with sepsis, shock and obstruction; never assume that stopping one medicine is sufficient without treating the underlying physiology.
Common nephrotoxic exposures
| Exposure | Mechanism/pattern | Emergency precautions |
|---|---|---|
| NSAIDs | Reduce renal prostaglandin-mediated blood flow; risk rises with dehydration, CKD, ACE inhibitor/ARB and diuretic use. | Review over-the-counter use, stop avoidable exposure and assess perfusion/creatinine. |
| Aminoglycosides/vancomycin | Tubular injury, especially with high troughs, prolonged therapy or other nephrotoxins. | Therapeutic drug monitoring and renal dose adjustment. |
| Amphotericin and selected antivirals | Tubular toxicity, electrolyte wasting or crystal injury. | Monitor renal function, potassium, magnesium and hydration plan. |
| ACE inhibitors/ARBs and diuretics | Can reduce filtration during hypovolaemia or renal artery disease; potassium may rise. | Review during acute illness under prescriber guidance; never stop essential medicines without a plan. |
| Iodinated contrast | Risk is higher with CKD, AKI, diabetes, dehydration and repeated exposure. | Assess risk and hydrate appropriately; do not delay lifesaving imaging. |
| Herbal/traditional medicines and heavy metals | Unknown ingredients, contamination, direct toxicity or adulterated drugs. | Ask non-judgmentally, preserve packaging/sample and notify toxicology/public health when needed. |
| Chemotherapy and immunosuppressants | Tubular, glomerular or vascular injury; tumour lysis may cause AKI. | Follow oncology protocol, monitor urate/electrolytes and involve renal services. |
Risk factors and high-risk combinations
- Pre-existing CKD, a single kidney, renal transplant, diabetes, heart failure, liver disease or older age.
- Dehydration from diarrhoea, vomiting, fever, fasting, burns or poor access to water.
- Sepsis, hypotension, haemorrhage, major surgery, trauma, rhabdomyolysis or pregnancy complications.
- “Triple whammy” exposure: NSAID plus ACE inhibitor/ARB plus diuretic during volume depletion.
- Multiple antimicrobials, contrast repeated within a short interval or unmonitored high-dose medicines.
- Unclear medicines from multiple clinics, self-medication, herbal mixtures or contaminated products.
First-contact assessment
- Bring the patient to a monitored area if hypotensive, oliguric, breathless, confused, hyperkalaemic or systemically toxic.
- Ask what was taken, dose, timing, route, treatment course, last normal dose, co-medications, herbal products and possible overdose.
- Establish baseline creatinine, urine output, body weight, dialysis status and allergies.
- Check ABCDE, glucose, ECG, perfusion, fluid status, lungs, oedema, rash, bladder and catheter function.
- Stop further avoidable exposure and call senior, renal, pharmacy or toxicology support early.
ABCDE and emergency complications
| Threat | Clues | Immediate response |
|---|---|---|
| Hyperkalaemia | Weakness, paraesthesia, peaked T waves, broad QRS or arrhythmia. | ECG, hyperkalaemia protocol, stop potassium sources and prepare renal replacement if refractory. |
| Pulmonary oedema | Dyspnoea, orthopnoea, crackles, hypoxia, oedema or weight gain. | Upright position, oxygen/ventilation, fluid review, diuretic/dialysis assessment. |
| Acidosis/uraemia | Kussmaul breathing, confusion, asterixis, nausea, pericarditis or bleeding. | Blood gas, renal/critical-care review and treat cause; consider dialysis. |
| Shock/volume depletion | Hypotension, tachycardia, dry mucosa, cold peripheries or low urine. | Carefully reassessed isotonic fluid, sepsis/bleeding treatment and avoid nephrotoxin continuation. |
| Anaphylaxis/toxin syndrome | Rash, bronchospasm, bradycardia, secretions, altered state or seizures. | Emergency resuscitation and poison-specific protocol; protect airway. |
Investigations and monitoring
- Serial creatinine, urea, eGFR, potassium, sodium, bicarbonate, calcium, phosphate and magnesium.
- Urinalysis, microscopy, culture, urine protein and specific gravity when appropriate.
- FBC, blood gas, glucose, CK, liver tests, inflammatory markers, cultures and lactate according to presentation.
- ECG for potassium risk and continuous monitoring when arrhythmia or severe electrolyte abnormality is possible.
- Ultrasound for obstruction, bladder retention, renal size and alternative pathology.
- Drug concentrations when available, including selected aminoglycosides, vancomycin, lithium, digoxin or anticonvulsants.
- Accurate urine output, daily weight, fluid balance and medicine administration time.
Immediate treatment principles
- Stop or withhold the suspected nephrotoxin when clinically safe and document the decision.
- Correct dehydration or shock with carefully reassessed isotonic fluid; avoid fluid overload in CKD/heart failure.
- Treat sepsis, obstruction, rhabdomyolysis, hyperkalaemia, acidosis and other contributors immediately.
- Adjust all renally cleared medicines using current renal function and pharmacy/renal advice.
- Do not use loop diuretics to force urine production in a euvolaemic patient; reserve for clinically important overload under prescription.
- Discuss urgent dialysis for refractory potassium/acidosis, pulmonary oedema, uraemic complications or a dialysable toxin.
Contrast-associated risk
- Identify AKI, CKD, diabetes, dehydration, heart failure, age and recent contrast exposure before elective contrast.
- Use the lowest appropriate contrast dose and avoid unnecessary repeat exposure.
- Do not delay emergency CT/angiography when the diagnostic benefit is lifesaving; communicate risk and protect renal perfusion.
- Use an appropriate hydration plan, avoid concurrent nephrotoxins and repeat renal tests in high-risk patients.
Antimicrobials and dose adjustment
Antibiotics can be lifesaving, and fear of nephrotoxicity must not cause undertreatment of sepsis. The safer approach is timely culture-guided therapy, renal dose adjustment, therapeutic monitoring where available, avoidance of unnecessary combinations and daily review for de-escalation.
- Record weight, baseline renal function, dose, interval, start time and indication.
- Review aminoglycoside and vancomycin levels according to local protocol.
- Use pharmacy/renal input for dialysis patients and changing renal function.
- Monitor rash, fever, eosinophilia, haematuria and proteinuria for interstitial or glomerular injury.
Overdose and toxic exposure
- Protect staff and patient, remove contaminated clothing when appropriate and follow decontamination guidance.
- Bring packaging, prescriptions, herbal products or containers; record time and estimated dose.
- Support airway, breathing, circulation, glucose, temperature and seizures before focusing on the toxin.
- Call a poison centre/toxicology service and determine whether an antidote, enhanced elimination or dialysis is indicated.
- Monitor for delayed kidney injury after apparently stable poisoning; arrange repeat creatinine and urine review.
Nursing interventions
- Complete medicine reconciliation, including non-prescription and traditional products, at every transition of care.
- Measure urine output accurately and report oliguria/anuria promptly.
- Monitor BP, ECG, respiratory status, fluid balance, daily weight, oedema, mental state and pain.
- Check every administration against renal dose, allergy, interaction and monitoring requirements.
- Maintain IV and catheter asepsis, protect skin and prepare safely for dialysis access if required.
- Teach patients to report reduced urine, swelling, breathlessness, muscle weakness, palpitations, vomiting or confusion.
Complications
| Complication | What to watch for | Escalation |
|---|---|---|
| Acute kidney injury | Rising creatinine, oliguria, haematuria, proteinuria or oedema. | Stop avoidable exposure, investigate cause and involve renal team. |
| Electrolyte dysregulation | Weakness, ECG changes, cramps, confusion or seizures. | Urgent ECG/electrolyte treatment and repeat monitoring. |
| Fluid overload | Hypoxia, crackles, pulmonary oedema or hypertension. | Fluid restriction, respiratory support and diuretic/dialysis review. |
| Interstitial nephritis | Fever, rash, eosinophilia, haematuria or creatinine rise after medicine. | Stop culprit, renal review and specialist treatment. |
| Dialysis need | Refractory acidosis, potassium, overload, uraemia or dialysable toxin. | Urgent renal replacement consultation. |
Prevention and safety systems
- Use electronic or paper alerts for CKD, previous AKI, allergies and high-risk medicines.
- Check renal function before and during nephrotoxic treatment; document a monitoring plan.
- Use weight-based dosing and current creatinine clearance/eGFR, recognising that rapidly changing AKI makes estimates imperfect.
- Avoid duplicate NSAIDs, unregulated mixtures and unnecessary contrast.
- Educate patients to show their medicine list to every provider and to seek help early during vomiting, diarrhoea, fever or reduced urine.
Clinical scenarios
Scenario 1 – NSAID and dehydration: A patient with diarrhoea has taken repeated ibuprofen and now passes little urine. Stop further NSAIDs, assess perfusion, check creatinine/potassium and give carefully reassessed fluid if hypovolaemic.
Scenario 2 – Antibiotic toxicity: A patient receiving gentamicin becomes oliguric with rising creatinine. Hold further doses pending senior/pharmacy review, check levels where available, treat sepsis, monitor electrolytes and involve renal services.
Scenario 3 – Herbal mixture: A young adult develops vomiting, weakness and AKI after an unknown herbal preparation. Stabilise ABCDE, preserve the product, call toxicology/public health, monitor potassium/acidosis and prepare dialysis discussion if needed.
Common errors to avoid
- Asking only about prescribed medicines and missing NSAIDs, herbs and supplements.
- Continuing nephrotoxins automatically after creatinine or urine output changes.
- Giving large fluids without checking lung findings or heart failure.
- Delaying treatment of sepsis because an antibiotic has renal risks.
- Failing to monitor potassium, magnesium, ECG and urine output.
- Using creatinine alone and ignoring baseline, trend and clinical volume status.
- Discharging without dose-adjusted prescriptions and repeat renal follow-up.
KIDNEY SAFE: K – Know baseline renal function; I – Identify every exposure; D – Dose-adjust; N – Note urine trend; E – ECG/electrolytes; Y – Yield to renal/toxicology advice; S – Stop avoidable toxins; A – Assess volume; F – Follow creatinine; E – Educate.
Revision questions
- What mechanisms allow medicines to cause kidney injury?
- List common nephrotoxic medicines and risk combinations.
- How should an EMT assess a patient with suspected drug-induced AKI?
- Why should emergency contrast imaging not automatically be withheld?
- What monitoring is needed for aminoglycosides or vancomycin?
- When should renal replacement therapy be discussed?
- Write a prevention plan for a patient discharged after nephrotoxic AKI.
Key takeaways
- Nephrotoxicity is often preventable through medication reconciliation and monitoring.
- Dehydration, sepsis, CKD and combinations magnify drug-related risk.
- Stop avoidable exposure, dose-adjust essential medicines and treat the underlying emergency.
- Monitor urine output, creatinine, potassium, acid-base status and ECG.
- Early renal/pharmacy/toxicology involvement prevents avoidable deterioration.