Nephrotoxicity

Nephrotoxicity is a poisonous effect of some substances, both toxic chemicals and medication, on the kidney. There are various forms of toxicity. Nephrotoxicity should not be confused with the fact that some medications have a predominantly renal excretion and need their dose adjusted for the decreased renal function (e.g. heparin).

Nephrotoxins are chemicals displaying nephrotoxicity.

The nephrotoxic effect of most drugs is more profound in patients who already suffer from renal impairment. Some drugs may affect renal function in more than one way.

Cardiovascular

 * General: diuretics, &beta;-blockers, vasodilator agents
 * Local: ACE inhibitors, ciclosporin.

Direct tubular effect

 * Proximal convoluted tubule: Aminoglycoside antibiotics (e.g. gentamicin), amphotericin B, cisplatin, radiocontrast media, immunoglobulins, mannitol
 * Distal tubule: NSAIDs (e.g. aspirin, ibuprofen, diclofenac), ACE inhibitors, ciclosporin, lithium salts, cyclophosphamide, amphotericin B
 * Tubular obstruction: sulphonamides, methotrexate, aciclovir, polyethylene glycol.

Acute interstitial nephritis

 * &beta;-lactam antibiotics, vancomycin, rifampicin, sulphonamides, ciprofloxacin, NSAIDs, ranitidine, cimetidine, furosemide, thiazides, phenytoin.

Acute glomerulonephritis

 * Penicillamine.

Causes of diabetes insipidus

 * Lithium salts
 * amphotericin B
 * fluoride
 * demeclocycline
 * foscarnet.

Other nephrotoxins

 * Heavy metals interfere with enzymes of energy metabolism.
 * Aristolochic acid, found in some plants and, more dangerously, in some herbal supplements derived from those plants, has been shown to have nephrotoxic effects on humans.

Surveillance
Nephrotoxicity is usually monitored through a simple blood test. An elevated level of creatinine indicates poor renal function. Normal creatinine levels are between 80 - 120 mm/l. In interventional radiology, a patients' creatinine levels are all checked prior to a procedure. Should an elevated creatinine level be found, a special contrast medium or radiocontrast is used which is less harmful for the patient.

Creatinine clearance is another measure of renal function, which may be more useful clinically when dealing with patients with early kidney disease.