Acute renal papillary necrosis induced by ibuprofen

Nonsteroidal antiinflammatory drugs, cyclooxygenase-2, and the kidneys

Nonsteroidal antiinflammatory drugs (NSAIDs) are one of the most commonly used classes of medications in the world, which function by inhibiting the cyclooxygenase (COX) enzymes and downregulating the inflammatory pathway. COX enzymes are constitutively expressed in the kidneys and function to maintain a homeostatic environment in terms of maintaining the glomerular filtration rate, blood pressure, sodium, water, and osmotic regulation. When the COX enzymes are inhibited by NSAIDs, a multitude of renal and vascular complications occur. This article aims to enlighten primary care physicians of the complications that arise with NSAIDs from a renal perspective and to present some management strategies.

Effects of 2-bromoethanamine on TonEBP expression and its possible role in induction of renal papillary necrosis in mice

Chronic analgesic abuse has been shown to induce severe renal injury characterized by renal papillary necrosis (RPN), an injury detectable at late stage. While direct toxicity of the drug may exist, the molecular mechanisms underlying analgesics induction of RPN remain unknown. A major limitation to study the pathogenesis of RPN is the required chronic exposure before detection of injury. Here, we employed 2-bromoethanamine (BEA) to simulate rapid papillary toxicity using inner medullary collecting duct (IMCD3) cells. Although exposure to 10μM BEA had no effect on cellular viability under isotonic conditions, a 50% loss in cell viability was observed in the first 24 h when cells were subjected to sublethal hypertonic stress and nearly complete cell death after 48 h suggesting that BEA exerts cytotoxicity only under hypertonic conditions. Because TonEBP is a transcription factor critical for cell survival during hypertonic conditions, we undertook experiments to examine the effect of BEA on TonEBP expression and activity. Exposure of cells to 10μM BEA resulted in a substantial reduction in TonEBP protein expression after 24 h. In addition, TonEBP was not translocated to the nucleus in BEA-treated IMCD3 cells under acute hypertonic stress for transcription of target genes essential for osmolyte accumulation. Finally, we found a substantial decrease in TonEBP expression in medullary kidney tissues of mice injected with a single ip dose of BEA. Our data suggest that TonEBP is a potential target for BEA leading to the process of papillary necrosis in the settings of hypertonic stress.

Nonsteroidal Anti-Inflammatory Drugs and the Kidney

Non-steroidal anti-inflammatory drugs (NSAIDs) inhibit the isoenzymes COX-1 and COX-2 of cyclooxygenase (COX). Renal side effects (e.g., kidney function, fluid and urinary electrolyte excretion) vary with the extent of COX-2-COX-1 selectivity and the administered dose of these compounds. While young healthy subjects will rarely experience adverse renal effects with the use of NSAIDs, elderly patients and those with co-morbibity (e.g., congestive heart failure, liver cirrhosis or chronic kidney disease) and drug combinations (e.g., renin-angiotensin blockers, diuretics plus NSAIDs) may develop acute renal failure. This review summarizes our present knowledge how traditional NSAIDs and selective COX-2 inhibitors may affect the kidney under various experimental and clinical conditions, and how these drugs may influence renal inflammation, water transport, sodium and potassium balance and how renal dysfunction or hypertension may result.

Acute renal failure in a patient with paroxysmal cold hemoglobinuria

Acute renal failure following auto-immune hemolysis is rare. We report a child with acute paroxysmal cold hemoglobinuria (PCH) complicated by renal failure. She was treated by peritoneal dialysis and red blood cell transfusion. After 2 weeks she had made a complete recovery with a normal blood count and renal profile, and the peritoneal dialysis catheter was removed. Extensive investigation, including an analysis of heme oxygenase-1 gene promoter region polymorphisms, failed to identify a cause for the renal failure in this patient.

COX-2 and the kidney

Nonsteroidal anti-inflammatory drugs (NSAIDs) are widely used for the treatment of pain and inflammation. Nonselective NSAIDs inhibit both cyclooxygenase (COX)-1 and COX-2. Nephrotoxicity of nonselective NSAIDs has been well documented. The effects of selective COX-2 inhibitors on renal function and blood pressure are attracting increasing attention. In the kidney, COX-2 is constitutively expressed and is highly regulated in response to alterations in intravascular volume. COX-2 metabolites have been implicated in the mediation of renin release, regulation of sodium excretion, and maintenance of renal blood flow. Similar to nonselective NSAIDs, inhibition of COX-2 may cause edema and modest elevations in blood pressure in a minority of subjects. COX-2 inhibitors may also exacerbate preexisting hypertension or interfere with other antihypertensive drugs. Occasional acute renal failure has also been reported. Caution should be taken when COX-2 inhibitors are prescribed, especially in high-risk patients (including elderly patients and patients with volume depletion).

Cardiorenal effects of celecoxib as compared with the nonsteroidal anti-inflammatory drugs diclofenac and ibuprofen

The cardiorenal safety database from the Celecoxib Long-term Arthritis Safety Study (CLASS) was analyzed to examine whether supratherapeutic doses of celecoxib are associated with decreased renal function and blood pressure (BP) effects compared with standard doses of diclofenac and ibuprofen in osteoarthritis (OA) and rheumatoid arthritis (RA) patients.In total, 8059 patients were enrolled; 7968 received at least one dose of study drug (RA: N = 2183; OA: N = 5785). Patients received celecoxib, 400 mg twice a day (b.i.d.). (N = 3987); ibuprofen, 800 mg three times a day. (N = 1985); or diclofenac, 75 mg b.i.d. (N = 1996). Effects measured included: investigator-reported hypertension, edema or congestive heart failure, clinically important BP elevations, incidence of patients starting new antihypertensive medication, and increases in serum creatinine or reductions in creatinine clearance. Celecoxib was associated with a similar incidence of hypertension or edema to diclofenac but significantly lower than ibuprofen. The celecoxib group had significantly fewer initiations of antihypertensives versus ibuprofen. Systolic BP increases of >20 mmHg and above 140 mmHg occurred significantly less often with celecoxib compared with ibuprofen or diclofenac. Changes in serum creatinine or estimated creatinine clearance occurred in a similar percentage of patients taking celecoxib or ibuprofen; modest differences were evident against diclofenac. In patients with mild prerenal azotemia, significantly fewer patients taking celecoxib exhibited clinically important reductions in renal function (3.7%), compared with diclofenac (7.3%; P < 0.05) and ibuprofen (7.3%; P < 0.05). A supratherapeutic dose of celecoxib was associated with an improved cardiorenal safety profile compared with standard doses of either ibuprofen or diclofenac.

Renal papillary necrosis induced by naproxen

A 17-year-old healthy girl was admitted to our hospital with diffuse abdominal pain and decreased oral intake of about 11 days duration. About a week prior to admission, she had taken naproxen, 250 mg four times a day for 4 days. Physical examination was normal except for diffuse abdominal tenderness on deep palpation. Investigations revealed high serum BUN (42 mg/dl) and creatinine (4.0 mg/dl). Serum electrolytes and complement (C3, C4) levels and urinalysis were normal. Antinuclear-antibody and anti-dsDNA were negative. Kidney biopsy revealed renal papillary necrosis, acute tubular necrosis, and focal interstitial nephritis. A diagnosis of nonoliguric acute renal failure due to naproxen nephrotoxicity was made. She received intravenous hydration, and oral steroids, which was gradually discontinued in 3 months. A follow-up at 4 months revealed normal renal function with a serum creatinine of 1.1 mg/dl, BUN 7 mg/dl, and normal urinalysis. The report highlights a need for caution while using naproxen or any other nonsteroidal anti-inflammatory drugs, even for a short duration.

Cyclooxygenase-2 inhibition and renal physiology

In the adult mammalian kidney, high levels of cyclooxygenase (COX)-2 expression can be detected in the macula densa and associated cortical thick ascending limb cells and medullary interstitial cells. In the renal cortex, COX-2 expression increases in high renin states, and selective COX-2 inhibitors significantly decrease plasma renin levels. In the medullary region of the kidney, the expression of COX-2 increases in response to a high-salt diet and water deprivation. The most important prostanoids in the kidney are prostaglandin (PG)I(2), or prostacyclin, and PGE(2). PGE(2) diminishes sodium reabsorption; thereby, its inhibition results in sodium retention that can manifest clinically in a variety of ways, such as peripheral edema, increased blood pressure (mainly in treated hypertensive patients), weight gain, and occasionally deterioration of heart failure. PGI(2) increases potassium secretion. As such, its inhibition can result in hyperkalemia, particularly in patients with underlying renal insufficiency. PGI(2) is also a potent vasodilator and helps maintain renal perfusion in conditions of decreased actual or effective circulating volume; its inhibition in such patients can result in acute renal failure. A variety of studies has been conducted to examine the effects of celecoxib and rofecoxib on renal function. These incorporate various study designs directly, making it virtually impossible to compare data across studies. It is apparent from such studies, coupled with published case reports, that the impact of both celecoxib and rofecoxib on renal function (including development of edema and hypertension) is similar to that of nonselective nonsteroidal anti-inflammatory drugs (NSAIDs). Studies comparing the 2 COX-2 inhibitors conflict in their interpretation. Overall, the data suggest similar effects on renal function among all NSAIDs when used at comparable doses.

Renal effects of cyclooxygenase-2 selective inhibitors

Recent in-vitro and animal data show that cyclooxygenase-2 has an integral role in the physiology and pathophysiology of the kidney. Cyclooxygenase-2 regulates renin-angiotensin secretion, and thereby glomerular filtration rate and sodium homeostasis. It is also important for protecting against hypertonic stress. As a consequence, it is not surprising that clinical data verify that selective inhibitors of cyclooxygenase-2 affect renal function to a degree similar to that which has previously been documented with nonselective nonsteroidal anti-inflammatory drugs.

Nephrotoxicity of nonsteroidal anti-inflammatory drugs: physiologic foundations and clinical implications

Although the prevalence of nephrotoxicity in patients treated with nonsteroidal anti-inflammatory drugs (NSAIDs) is relatively low, the extensive use profile of these agents implies that many persons are at risk. At basal states of normal renal function, the role of renal prostaglandin production for maintenance of stable renal hemodynamic function is relatively limited. Nonetheless, in the clinical setting of reduced renal perfusion as seen in various forms of cardio-renal disease, dehydration, and the aging kidney, the adequacy of renal prostaglandin production mediated predominantly by cyclooxygenase-1 (COX-1) and, potentially, by COX-2 enzyme activity becomes of major significance in the activation of compensatory renal hemodynamics. Inhibition of renal prostaglandin production by the use of NSAIDs in these circumstances can potentially lead to the emergence of several distinct syndromes of disturbed renal function. These include fluid and electrolyte disorders, acute renal dysfunction, nephrotic syndrome/ interstitial nephritis, and renal papillary necrosis. In addition, by blunting the homeostatic renal effects of prostaglandins, NSAIDs can adversely influence blood pressure control, particularly during the use of angiotensin-converting enzyme (ACE) inhibitors, diuretics, and beta blockers. This is a matter of considerable public health concern, in that some 12 million US citizens are concurrently treated with NSAIDs and antihypertensive drugs. Finally, the risk of congestive heart failure is significantly increased when NSAIDs are given to patients receiving diuretic therapy who have cardiovascular risk factors. Physiologic factors, clinical presentations, diagnostic modalities, and clinical management strategies appropriate to these NSAID-induced renal syndromes are described.