Drug-induced renal toxicity. Help in recognizing offending agents

Acute Renal Failure and the Critically Ill Patient

Acute renal failure (ARF) is a complication frequently observed in critically ill patients. This review provides details regarding the epidemiology and overall care of the ARF patient. ARF is defined and classified based on etiology. These classifications are prerenal azotemia, ischemic ARF, and postrenal azotemia. Examples of drug-induced nephrotoxicity are also outlined. Clinical presentation and diagnostic criteria of ARF are differentiated among the major ARF classes, and management strategies are outlined. These management strategies include preventive, supportive, pharmacologic, and nonpharmacologic interventions. Current standards of practice and investigational therapies are also discussed. Pharmacokinetic monitoring and dosing regimen adjustments in ARF patients with and without renal replacement therapy are reviewed. Finally, a prognostic evaluation of ARF in critically ill patients is provided based on current knowledge of the disease state and treatment options.

The role of medications and their management in acute kidney injury

Prior to 2002, the incidence of acute renal failure (ARF) varied as there was no standard definition. To better understand its incidence and etiology and to develop treatment and prevention strategies, while moving research forward, the Acute Dialysis Quality Initiative workgroup developed the RIFLE (risk, injury, failure, loss, end-stage kidney disease) classification. After continued data suggesting that even small increases in serum creatinine lead to worse outcomes, the Acute Kidney Injury Network (AKIN) modified the RIFLE criteria and used the term acute kidney injury (AKI) instead of ARF. These classification and staging systems provide the clinician and researcher a starting point for refining the understanding and treatment of AKI. An important initial step in evaluating AKI is determining the likely location of injury, generally classified as prerenal, renal, or postrenal. There is no single biomarker or test that definitively defines the mechanism of the injury. Identifying the insult(s) requires a thorough assessment of the patient and their medical and medication histories. Prerenal injuries arise primarily due to renal hypoperfusion. This may be the result of systemic or focal conditions or secondary to the effects of drugs such as nonsteroidal anti-inflammatory drugs, calcineurin inhibitors (CIs), and modulators of the renin-angiotensin-aldosterone system. Renal, or intrinsic, injury is an overarching term that represents complex conditions leading to considerable damage to a component of the intrinsic renal system (renal tubules, glomerulus, vascular structures, inter-stitium, or renal tubule obstruction). Acute tubular necrosis and acute interstitial nephritis are the more common types of intrinsic renal injury. Each type of injury has several drugs that are implicated as a possible cause, with antiinfectives being the most common. Postrenal injuries that result from obstruction block the flow of urine, leading to hydronephrosis and subsequent damage to the renal parenchyma. Drugs associated with tubular obstruction include acyclovir, methotrexate, and several antiretrovirals. Renal recovery from drug-induced AKI begins once the offending agent has been removed, if clinically possible, and is complete in most cases. It is uncommon that renal replacement therapy will be needed while recovery occurs. Pharmacists can play a pivotal role in identifying possible causes of drug-induced AKI and limit their toxic effect by identifying those most likely to cause or contribute to injury. Dose adjustment is critical during changes in renal function, and the pharmacist can ensure that optimal therapy is provided during this critical time.

Acute kidney insufficiency in the critically ill

Acute kidney insufficiency (AKI), or injury, is common in the critically ill patient. Minimal increases in serum creatinine (Scr) have been associated with greater morbidity, mortality, and hospital cost. In 2002, the Acute Dialysis Quality Initiative (ADQI) proposed a consensus definition (the RIFLE classification) which was modified after continuing evidence suggested that small changes in Scr (≥0.3 mg/dL) led to worsening outcomes. This group, known as the Acute Kidney Injury Network (AKIN), suggests 3 stages of worsening kidney function. Such definitions may aid in identifying patients at greatest risk and further the development of preventive strategies. This review will focus on the epidemiology and etiology of AKI as well as provide a mechanistic description of drug-induced AKI. In addition, a brief review of continuous renal replacement therapies is provided.

Pharmacokinetics of gentamicin in rabbits pretreated with nonsteroidal anti-inflammatory drugs: an interaction study

Interaction between nonsteroidal anti-inflammatory drugs (NSAIDs) and other drugs occurs relatively frequently because of the wide use of NSAIDs. Such interactions with drugs of narrow therapeutic index used in serious disease states may lead to toxicity. Gentamicin toxicity is based on its concentration in serum, and any alteration in pharmacokinetic parameters may lead to gentamicin accumulation in the body and subsequently to severe nephrotoxicity and ototoxicity. To test this hypothesis, the effect of pretreatment with NSAIDs on gentamicin pharmacokinetics was examined in rabbit. Gentamicin sulfate (5 mg/kg) was administered to rabbits pretreated with aspirin (300 mg/kg), ketorolac tromethamine (3 mg/kg), ibuprofen (20 mg/kg), and piroxicam (2 mg/kg) twice a day for 1 week. The pretreatment with NSAIDs had significant effects on the body clearance and maximum concentration. Aspirin, piroxicam and ketorolac tromethamine pretreatment had significant effects on the area under the curve of gentamicin versus time. Aspirin and ketorolac tromethamine pretreatment had significant effects on the half-life of gentamicin. Aspirin had a significant effect on the volume of distribution of gentamicin. These results suggest that pretreatment with NSAIDs alters the pharmacokinetics of gentamicin and leads to accumulation inside the body, which could result in toxicity.