Renal complications of nonsteroidal anti-inflammatory drugs

[Emergencies in nephrology]

Emergencies in nephrology are mainly acute life-threatening situations for patients. Furthermore, one needs to consider constellations that are so damaging to the kidneys that the need for permanent dialysis develops within a short period of time. Acute kidney failure as an immediate consequence is categorized using the Acute Kidney Injury Network (AKIN) stages and is pathophysiologically subdivided into pre-, intra- and post-renal. This leads to changes in volume status, acid base and electrolytes, while the terms nephrotic and nephritic describe the amount of kidney damage and help to choose diagnostic steps wisely. Patients that are already undergoing dialysis treatment or have received a kidney transplant are a further specific group in the case of emergencies.

Navigating sarcopenia in COVID-19 patients and survivors: Understanding the long-term consequences, transitioning from hospital to community with mechanisms and interventions for future preparedness

The coronavirus disease 2019 (COVID-19) pandemic has caused widespread devastation, with millions of confirmed cases and deaths worldwide. Although there were efforts made to develop treatments and vaccines for COVID-19, the coexistence of sarcopenia, a muscle disorder, has been largely overlooked. It is while new variants of this disease (eg, BA.2.86) are challenging the current protocols. Sarcopenia is associated with increased mortality and disability, and shares common mechanisms with COVID-19, such as inflammation, hormonal changes, and malnutrition. This can worsen the effects of both conditions. Furthermore, survived patients with COVID-19 who have elevated risk, as well as aging, which increases the process of sarcopenia. Therefore, addressing sarcopenia in patients with COVID-19 and surviving individuals can be crucial for improving outcomes and preventing long-term disability. During hospital stays, assessing sarcopenia through indicators like muscle wasting and malnutrition is important. Nutritional interventions, such as malnutrition screening and enteral feeding, play a critical role in preventing sarcopenia in hospitals. Mental health and physical activity evaluations and interventions are also necessary. Even after recovering from COVID-19, there is a risk of developing sarcopenia, requiring continued monitoring. Nutrition and physical activity considerations are vital for prevention and management, necessitating tailored training programs and diet therapy. Mental health should not be overlooked, with regular screening, and community-based interventions. Infrastructure should support physical activity, and mental health services must become more accessible. Community engagement through support groups and peer networks can foster resilience and social connection. Efforts are needed to promote healthy diets and ensure access to nutritious foods.

Legal Performance-enhancing Drugs Alter Course and Treatment of Rhabdomyolysis-induced Acute Kidney Injury

INTRODUCTION

Rhabdomyolysis-induced acute kidney injury (RIAKI) can interrupt physical training and increase mortality in injured warfighters. The legal performance-enhancing drugs caffeine and ibuprofen, which can cause renal injury, are widely used by service members. Whether caffeine or ibuprofen affects RIAKI is unknown. Cilastatin treatment was recently identified as an experimental treatment to prevent RIAKI at injury. To determine potential interacting factors in RIAKI treatment, we test the hypothesis that caffeine and ibuprofen worsen RIAKI and interfere with treatment.

MATERIALS AND METHODS

In mice, RIAKI was induced by glycerol intramuscular injection. Simultaneously, mice received caffeine (3 mg/kg), ibuprofen (10 mg/kg), or vehicle. A second cohort received volume resuscitation (PlasmaLyte, 20 mL/kg) in addition to caffeine or ibuprofen. In a third cohort, cilastatin (200 mg/kg) was administered concurrently with drug and glycerol administration. Glomerular filtration rate (GFR), blood urea nitrogen (BUN), urine output (UOP), renal pathology, and renal immunofluorescence for kidney injury molecule 1 were quantified after 24 hours.

RESULTS

Caffeine did not worsen RIAKI; although BUN was modestly increased by caffeine administration, 24-hour GFR, UOP, and renal histopathology were similar between vehicle-treated, caffeine-treated, and caffeine + PlasmaLyte-treated mice. Ibuprofen administration greatly worsened RIAKI (GFR 14.3 ± 19.5 vs. 577.4 ± 454.6 µL/min/100 g in control, UOP 0.5 ± 0.4 in ibuprofen-treated mice vs. 2.7 ± 1.7 mL/24 h in control, and BUN 264 ± 201 in ibuprofen-treated mice vs. 66 ± 21 mg/dL in control, P < .05 for all); PlasmaLyte treatment did not reverse this effect. Cilastatin with or without PlasmaLyte did not reverse the deleterious effect of ibuprofen in RIAKI.

CONCLUSIONS

Caffeine does not worsen RIAKI. The widely used performance-enhancing drug ibuprofen greatly worsens RIAKI in mice. Standard or experimental treatment of RIAKI including the addition of cilastatin to standard resuscitation is ineffective in mice with RIAKI exacerbated by ibuprofen. These findings may have clinical implications for the current therapy of RIAKI and for translational studies of novel treatment.

Anti-inflammatory activity of pyridazinones: A review

The pyridazinone core has emerged as a leading structure for fighting inflammation, with low ulcerogenic effects. Moreover, easy functionalization of various ring positions of the pyridazinone core structure makes it an attractive synthetic and therapeutic target for the design and synthesis of anti-inflammatory agents. The present review surveys the recent advances of pyridazinone derivatives as potential anti-inflammatory agents to provide insights into the rational design of more effective anti-inflammatory pyridazinones.

Over-The-Counter Remedies in Older Adults: Patterns of Use, Potential Pitfalls, and Proposed Solutions

Over-the-counter (OTC) products such as pharmaceuticals, dietary supplements, vitamins, and herbal remedies are widely available and copiously used by older adults for health maintenance and symptom management. Owing to physiology, multimorbidity, and polypharmacy, this population is particularly vulnerable to inappropriate use of OTC products, adverse effects, and drug interactions. While OTC pharmaceuticals are bound by FDA-approved standards, dietary supplements are regulated differently, resulting in variable quality and increased possibility for adulteration. Internationally, standards for OTC products vary widely. Accessible educational information, improved provider-patient communication, and revision of regulatory policy could improve safety for older adult users of OTC products.

Renal Microvascular Ischemia Secondary to Nonsteroidal Anti-inflammatory Drugs

Nonsteroidal anti-inflammatory drugs (NSAIDs), widely prescribed for pain, can affect kidneys in various ways. We present a case of a 37-year-old woman with multiple NSAIDs intake over a short period for dysmenorrhea followed by the development of new-onset bilateral flank pain. Computed tomography revealed bilateral multiple renal infarcts. Renal function was normal. Investigations showed no cardiac or renal artery lesion and vasculitis work-up was negative. She was treated conservatively and further NSAID intake was avoided. Follow-up scan showed complete restoration of the blood flow in previously affected areas. Thus, microvascular ischemia secondary to NSAIDs was thought to be responsible.

Nonsteroidal Anti-Inflammatory Drugs: Updates on Dosage Formulations and Adverse Effects

Nonsteroidal anti-inflammatory drugs (NSAIDs) are commonly used medications due to their prescription and nonprescription availability, various dosage formulations, and therapeutic efficacy. Although NSAIDs have many known benefits, their effects on gastrointestinal, cardiovascular, bone, and renal physiology limit their widespread and long-term use. This article provides an update on dosage formulations, product availability, and pertinent adverse effects and warnings regarding the use of NSAIDs, with an emphasis on nonaspirin NSAIDs.

Toxicological Evaluation of Novel Cyclohexenone Derivative in an Animal Model through Histopathological and Biochemical Techniques

Toxicity studies were conducted to provide safety data of potential drug candidates by determining lethal and toxic doses. This study was designed for pre-clinical evaluation of novel cyclohexenone derivative with respect to the acute and sub-acute toxicity along with the diabetogenic potential. Acute and sub-acute toxicity were assessed after intraperitoneal (i.p) injection of the investigational compound through selected doses for 21 days. This was followed by assessment of isolated body organs (liver, kidney, heart and pancreas) via biochemical indicators and histopathological techniques. No signs of toxicity were revealed in the study of acute toxicity. Similarly, a sub-acute toxicity study showed no significant difference in biochemical indicators on 11th and 21st days between treated and control groups. However, in blood urea nitrogen (BUN) and random blood glucose/sugar (RBS) values, significant differences were recorded. Histopathological evaluation of liver, kidney, pancreas and heart tissues revealed mild to severe changes in the form of steatosis, inflammation, fibrosis, necrosis and myofibrillary damages on 11th and 21st days of treatment. In conclusion, the median lethal dose of the tested compound was expected to be greater than 500 mg/kg. No significant change occurred in selected biomarkers, except BUN and RBS levels, but a histopathological study showed moderate toxic effect on liver, kidney, pancreas and heart tissues by the cyclohexenone derivative.

Efficacy and safety of gout flare prophylaxis and therapy use in people with chronic kidney disease: a Gout, Hyperuricemia and Crystal-Associated Disease Network (G-CAN)-initiated literature review

Gout flare prophylaxis and therapy use in people with underlying chronic kidney disease (CKD) is challenging, given limited treatment options and risk of worsening renal function with inappropriate treatment dosing. This literature review aimed to describe the current literature on the efficacy and safety of gout flare prophylaxis and therapy use in people with CKD stages 3-5. A literature search via PubMed, the Cochrane Library, and EMBASE was performed from 1 January 1959 to 31 January 2018. Inclusion criteria were studies with people with gout and renal impairment (i.e. estimated glomerular filtration rate (eGFR) or creatinine clearance (CrCl) < 60 ml/min/1.73 m²), and with exposure to colchicine, interleukin-1 inhibitors, non-steroidal anti-inflammatory drugs (NSAIDs), and glucocorticoids. All study designs were included. A total of 33 studies with efficacy and/or safety analysis stratified by renal function were reviewed-colchicine (n = 20), anakinra (n = 7), canakinumab (n = 1), NSAIDs (n = 3), and glucocorticoids (n = 2). A total of 58 studies reported these primary outcomes without renal function stratification-colchicine (n = 29), anakinra (n = 10), canakinumab (n = 6), rilonacept (n = 2), NSAIDs (n = 1), and glucocorticoids (n = 10). Most clinical trials excluded study participants with severe CKD (i.e. eGFR or CrCl of < 30 mL/min/1.73 m²). Information on the efficacy and safety outcomes of gout flare prophylaxis and therapy use stratified by renal function is lacking. Clinical trial results cannot be extrapolated for those with advanced CKD. Where possible, current and future gout flare studies should include patients with CKD and with study outcomes reported based on renal function and using standardised gout flare definition.

Prominent Indomethacin-Induced Enteropathy in Fcgriib Defi-cient lupus Mice: An Impact of Macrophage Responses and Immune Deposition in Gut

A high dose of NSAIDs, a common analgesic, might induce lupus activity through several NSAIDs adverse effects including gastrointestinal permeability defect (gut leakage) and endotoxemia. Indomethacin (25 mg/day) was orally administered for 7 days in 24-wk-old Fc gamma receptor IIb deficient (FcgRIIb-/-) mice, an asymptomatic lupus model (increased anti-dsDNA without lupus nephritis), and age-matched wild-type (WT) mice. Severity of indomethacin-induced enteropathy in FcgRIIb-/- mice was higher than WT mice as demonstrated by survival analysis, intestinal injury (histology, immune-deposition, and intestinal cytokines), gut leakage (FITC-dextran assay and endotoxemia), serum cytokines, and lupus characteristics (anti-dsDNA, renal injury, and proteinuria). Prominent responses of FcgRIIb-/- macrophages toward lipopolysaccharide (LPS) compared to WT cells due to the expression of only activating-FcgRs without inhibitory-FcgRIIb were demonstrated. Extracellular flux analysis indicated the greater mitochondria activity (increased respiratory capacity and respiratory reserve) in FcgRIIb-/- macrophages with a concordant decrease in glycolysis activity when compared to WT cells. In conclusion, gut leakage-induced endotoxemia is more severe in indomethacin-administered FcgRIIb-/- mice than WT, possibly due to the enhanced indomethacin toxicity from lupus-induced intestinal immune-deposition. Due to a lack of inhibitory-FcgRIIb expression, mitochondrial function, and cytokine production of FcgRIIb-/- macrophages were more prominent than WT cells. Hence, lupus disease-activation from NSAIDs-enteropathy-induced gut leakage is possible.

Comparison of the efficacy of erector spinae plane block and peritubal infiltration of levobupivacaine for postoperative analgesia following percutaneous nephrolithotomy

Background and Aims:

Erector spinae plane (ESP) block is a simple and safe interfascial plane block reported to provide good analgesia after thoracolumbar surgeries. We compared its efficacy with conventional peritubal local anesthetic infiltration following percutaneous nephrolithotomy (PCNL).

Material and Methods:

A total of 60 adult patients posted for elective PCNL were randomly allocated into two groups. Postoperatively, Group I received ultrasound (US) guided peritubular infiltration block with 20 ml of 0.25% levobupivacaine and Group II received US guided ESP block with 20 ml of 0.25% levobupivacaine. The two groups were compared for the time to first rescue analgesic (Injection tramadol), number of rescue analgesic demands, total analgesic consumption in first 24 hours, VAS (rest and dynamic) scores and the adverse effects. The data were analyzed by unpaired t-test and Mann Whitney U test.

Results:

The time to first rescue analgesic demand was significantly longer in Group II (6.93 ± 2.15 h vs. 16.21 ± 7.53 h). The VAS scores (rest and dynamic) at eight and twelve hours of measurement were significantly lower in Group II (P < 0.05). The number of analgesic demands were less in group II (2.97 ± 0.49 vs. 1.00 ± 1.05). The total analgesic consumption in first 24 hours was less in Group II (148.33 ± 24.51 mg vs. 51.92 ± 45.78 mg).

Conclusion:

ESP block is a very effective and safe technique to provide prolonged duration of postoperative analgesia following PCNL. Peritubal local anesthetic infiltration is also a reliable technique for postoperative analgesia.

Nonopioid Approaches to Pain Management in Chronic Kidney Disease

Patients with chronic kidney disease (CKD) and end-stage renal disease experience high pain and symptom burden, but management of chronic pain in this population remains challenging. Recent studies have shown a high rate of opioid prescription and use in patients with kidney disease. However, the concern for opioid-related morbidity and mortality suggests a need to reconsider the safety and efficacy of opioid use in patients with CKD. In this review, we describe the current approaches to pain management in CKD, highlight the evolving opioid-related risks and kidney-specific concerns, and offer both pharmacologic and nonpharmacologic nonopioid strategies for pain management in patients with kidney disease, emphasizing the importance of using a multimodal approach to optimize pain control.

Ibuprofen Safety at the Golden Anniversary: Are all NSAIDs the Same? A Narrative Review

Ibuprofen first came to market about 50 years ago and rapidly moved to over-the-counter (OTC) sales. In April 2019, the National Agency for the Safety of Medicines and Health Products (ANSM) of France issued a warning for NSAID uses by patients with infectious diseases based on an analysis of 20 years of real-world safety data on ibuprofen and ketoprofen. Nevertheless, ibuprofen remains a mainstay in the analgesic armamentarium and with numerous randomized clinical trials, head-to-head studies, and decades of clinical experience. The authors offer a review of the safety of ibuprofen and how it may differ from other NSAIDs. Ibuprofen is associated with certain well-known gastrointestinal adverse effects that are related to dose and patient population. Among nonsteroidal anti-inflammatory drugs (NSAIDs), ibuprofen has a comparatively low risk of cardiovascular adverse effects. It has been associated with renal and hepatic adverse effects, which appear to depend on dose, concomitant medications, and patient population. The association of ibuprofen with infections is more complex in that it confers risk in some situations but benefits in others, the latter in cystic fibrosis. Emerging interest in the literature is providing evidence of the role of ibuprofen as a possible endocrine disrupter as well as its potential antiproliferative effects for cancer cells. Taken altogether, ibuprofen has a favorable safety profile and is an effective analgesic for many acute and chronic pain conditions, although it-like other NSAIDs-is not without risk. After 50 years, evidence is still emerging about ibuprofen and its unique safety profile among NSAIDs. FUNDING: The Rapid Service Fee was funded by Abbott Established Pharmaceuticals Division (EPD).

Immunomodulatory actions of a Polynesian herb Noni (Morinda citrifolia) and its clinical applications

Morinda citrifolia (Noni) is a popular traditional medicinal plant consumed in various forms in several countries around the world as a complementary and alternative treatment due to its established health benefits. Noni is rich in bioactive substances and has significantly exhibited pro-oxidant and immunomodulatory effects. In this review, we highlight the pharmacological basis related to the phytochemicals and polysaccharides present in Noni and its potential therapeutic effects. We screened electronic databases such as PubMed, Google Scholar, Scopus for scientific literature. Our results indicate that Noni is beneficial for various diseases with its crude extracts showing therapeutic benefit for a wide range of pathological diseases. We believe that further pharmacological and toxicological studies in addition to well-designed controlled clinical trials can validate Noni to be an effective and novel natural product for prophylactic and therapeutic use of several diseases.

Cardio-renal safety of non-steroidal anti-inflammatory drugs

Non-steroidal anti-inflammatory drugs (NSAIDs) are among the most widely used therapeutic class in clinical medicine. These are sub-divided based on their selectivity for inhibition of cyclooxygenase (COX) isoforms (COX-1 and COX-2) into: (1) non-selective (ns-NSAIDs), and (2) selective NSAIDs (s-NSAIDs) with preferential inhibition of COX-2 isozyme. The safety and pathophysiology of NSAIDs on the renal and cardiovascular systems have continued to evolve over the years following short- and long-term treatment in both preclinical models and humans. This review summarizes major learnings on cardiac and renal complications associated with pharmaceutical inhibition of COX-1 and COX-2 with focus on preclinical to clinical translatability of cardio-renal data.

Effect of infraorbital nerve block on postoperative pain and 30-day morbidity at the donor site in buccal mucosal graft urethroplasty

Background and Aims

Buccal mucosa harvest for substitution urethroplasty can be painful, and may be associated with long-term complications such as perioral numbness, persistent difficulty with mouth opening, and change in salivary function. This study was designed to evaluate the efficacy of infraorbital nerve block (IOB) in relieving postoperative pain at the donor site of the buccal mucosal graft (BMG) and its associated morbidity at 30 days.

Material and Methods

Thirty adults scheduled for BMG urethroplasty were enrolled in this study and were randomized to receive either no block group I (control) and IOB group II intraorally with 1 mL of 0.5% bupivacaine. Pain was assessed by visual analog scale, intraoral morbidity, and patient satisfaction in the immediate postoperative period. All patients were reviewed after 1 month for morbidity such as perioral numbness, pain on mastication, and tightness on mouth opening. Statistical analysis was done using Mann-Whitney's U and Chi-square tests.

Results

Median time to pain-free oral intake for liquids (group I: 2-5 days, group II: 1 day, P < 0.001) and solids (group I: 4 days, group II: 2 days, P < 0.001) was earlier in group II. At the follow-up after 1 month, one patient in group II and three patients in group I showed perioral numbness (P = 0.026), and five patients had pain on mastication in group I (P = 0.016).

Conclusion

IOB is associated with postoperative analgesia and facilitation of early food intake, mitigating the morbidity of the donor site and provides satisfaction.

Maligned non-steroidal anti-inflammatory drugs: Misunderstanding of their safety profile in patients with renal insufficiency

Non-steroidal anti-inflammatory drugs have a fundamental and pivotal position in management of many of the disorders managed by rheumatologists. Promulgation of a false perspective of their toxicity has compromised our ability to advise our patients and participate in the management of their disorders. The literature sources, from which the false perspective derives, do not accurately reflect safety and fail to address the value of appropriate drug use monitoring. We, as rheumatologists, must stand up and proactively address engrained misconceptions-if we are to be able to continue to provide safe, effective care for our patients.

Novel renal markers for the assessment of renal integrity in patients undergoing knee arthroplasty - a pilot study

Background

The feasibility of novel kidney injury biomarkers in consecutive patients having total knee arthroplasty with local infiltration analgesia was evaluated.

Methods

We enrolled 30 patients scheduled for elective unilateral total knee arthroplasty. Paired plasma and urine samples were taken before surgery and at 4 h, 24 h and 48 h after surgery to measure creatinine, cystatin C, neutrophil gelatinase associated lipocalin, kidney injury molecule-1, interleukin-18 and liver-type fatty acid-binding protein.

Results

At baseline, 13 subjects had normal kidney function, 15 had mild and two had moderate kidney failure evaluated by calculated glomerular filtration rate. None of the subjects had all measured novel renal markers below proposed cut-off concentrations. Altogether 28/30 subjects had one (n = 3), two (n = 7) or three (n = 18) plasma neutrophil gelatinase associated lipocalin values above normal. In seven of these 28 subjects plasma creatinine, calculated glomerular filtration rate and plasma cystatin C were within the reference values. Five subjects had a low urine output, < 0.5 mL/h, indicating transient acute kidney injury, four of these had high plasma neutrophil gelatinase associated lipocalin and one high plasma cystatin C.

Conclusions

In the present study plasma neutrophil gelatinase associated lipocalin was elevated in most subjects with total knee arthroplasty and local infiltration analgesia as a marker of possible renal proximal tubular injury. Five subjects had transient low urine output, but none developed renal deterioration requiring treatment.

Hyporeninemic hypoaldosteronism in a patient with diabetes mellitus: an unforgettable case report

A 58-year-old man presented with a 3-year history of chronic and intermittent hyperkalemia requiring recurrent attendances to the emergency department for urgent treatment. His medical history included secondary diabetes mellitus following a bout of acute pancreatitis and a previous splenectomy for a spontaneous splenic rupture. He also had a history of prolonged use of non-steroidal anti-inflammatory drugs for back pain and painful neuropathy. He was not on any medication or diet that would cause a raised serum potassium level and his renal function was normal. He was on a basal-bolus insulin regimen but his diabetes control had been poor for several years. As the hyperkalemia had gone on for so long in the presence of normal renal function, he went on to have further tests. Adrenal insufficiency had been ruled out following a short Synacthen test. Further investigations revealed low serum aldosterone levels and inappropriately low serum renin levels in the presence of hyperkalemia. This was suggestive of hyporeninemic hypoaldosteronism (HH). He was then treated with fludrocortisone and furosemide and his serum potassium levels remained normal. Additionally, he did not require any more emergency admissions to treat hyperkalemia thereafter. It was concluded that the HH-induced hyperkalemia was caused by diabetes mellitus or due to a combination of diabetes and prolonged use of non-steroidal anti-inflammatory drugs. The absence of renal impairment may have contributed to the delay in diagnosis. HH is a commonly overlooked cause of hyperkalemia. This case highlights the fact that it should always be suspected when unexplained hyperkalemia is found in patients with only mild-moderately impaired renal function, especially in the presence of diabetes mellitus.

A randomized phase II feasibility trial of a multimodal intervention for the management of cachexia in lung and pancreatic cancer

BACKGROUND

Cancer cachexia is a syndrome of weight loss (including muscle and fat), anorexia, and decreased physical function. It has been suggested that the optimal treatment for cachexia should be a multimodal intervention. The primary aim of this study was to examine the feasibility and safety of a multimodal intervention (n-3 polyunsaturated fatty acid nutritional supplements, exercise, and anti-inflammatory medication: celecoxib) for cancer cachexia in patients with incurable lung or pancreatic cancer, undergoing chemotherapy.

METHODS

Patients receiving two cycles of standard chemotherapy were randomized to either the multimodal cachexia intervention or standard care. Primary outcome measures were feasibility assessed by recruitment, attrition, and compliance with intervention (>50% of components in >50% of patients). Key secondary outcomes were change in weight, muscle mass, physical activity, safety, and survival.

RESULTS

Three hundred and ninety-nine were screened resulting in 46 patients recruited (11.5%). Twenty five patients were randomized to the treatment and 21 as controls. Forty-one completed the study (attrition rate 11%). Compliance to the individual components of the intervention was 76% for celecoxib, 60% for exercise, and 48% for nutritional supplements. As expected from the sample size, there was no statistically significant effect on physical activity or muscle mass. There were no intervention-related Serious Adverse Events and survival was similar between the groups.

CONCLUSIONS

A multimodal cachexia intervention is feasible and safe in patients with incurable lung or pancreatic cancer; however, compliance to nutritional supplements was suboptimal. A phase III study is now underway to assess fully the effect of the intervention.

Measurement of gut permeability using fluorescent tracer agent technology

The healthy gut restricts macromolecular and bacterial movement across tight junctions, while increased intestinal permeability accompanies many intestinal disorders. Dual sugar absorption tests, which measure intestinal permeability in humans, present challenges. Therefore, we asked if enterally administered fluorescent tracers could ascertain mucosal integrity, because transcutaneous measurement of differentially absorbed molecules could enable specimen-free evaluation of permeability. We induced small bowel injury in rats using high- (15 mg/kg), intermediate- (10 mg/kg), and low- (5 mg/kg) dose indomethacin. Then, we compared urinary ratios of enterally administered fluorescent tracers MB-402 and MB-301 to urinary ratios of sugar tracers lactulose and rhamnose. We also tested the ability of transcutaneous sensors to measure the ratios of absorbed fluorophores. Urinary fluorophore and sugar ratios reflect gut injury in an indomethacin dose dependent manner. The fluorophores generated smooth curvilinear ratio trajectories with wide dynamic ranges. The more chaotic sugar ratios had narrower dynamic ranges. Fluorophore ratios measured through the skin distinguished indomethacin-challenged from same day control rats. Enterally administered fluorophores can identify intestinal injury in a rat model. Fluorophore ratios are measureable through the skin, obviating drawbacks of dual sugar absorption tests. Pending validation, this technology should be considered for human use.

Novel Therapies for Acute Kidney Injury

Acute kidney injury (AKI) is a common disease with a complex pathophysiology. The old paradigm of identifying renal injury based on location-prerenal, intrarenal, and postrenal-is now being supplanted with a new paradigm based on observable kidney injury patterns. The pathophysiology of AKI on a molecular and microanatomical level includes inflammation, immune dysregulation, oxidative injury, and impaired microcirculation. Treatment has traditionally been supportive, including the avoidance of nephrotoxins, judicious volume and blood pressure management, hemodynamic monitoring, and renal replacement therapy. Fluid overload and chloride-rich fluids are now implicated in the development of AKI, and resuscitation with a balanced, buffered solution at a conservative rate will mitigate risk. Novel therapies, which address specific observable kidney injury patterns include direct oxygen-free radical scavengers such as α-lipoic acid, curcumin, sodium-2-mercaptoethane sulphonate, propofol, and selenium. In addition, angiotensin II and adenosine receptor antagonists hope to ameliorate kidney injury via manipulation of renal hemodynamics and tubulo-glomerular feedback. Alkaline phosphatase, sphingosine 1 phosphate analogues, and dipeptidylpeptidase-4 inhibitors counteract kidney injury via manipulation of inflammatory pathways. Finally, genetic modifiers such as 5INP may mitigate AKI via transcriptive processes.

A comparison of the efficacy of intercostal nerve block and peritubal infiltration of ropivacaine for post-operative analgesia following percutaneous nephrolithotomy: A prospective randomised double-blind study

Background and Aims:

Intercostal nerve blockade (ICNB) and peritubal infiltration of the nephrostomy tract are well-established regional anaesthetic techniques for alleviating pain after percutaneous nephrolithotomy (PCNL). This prospective study compared the efficacy of ICNB and peritubal local anaesthetic infiltration of the nephrostomy tract in providing post-operative analgesia following PCNL.

Methods:

Sixty American Society of Anesthesiologist physical status 1 and II patients scheduled for PCNL requiring nephrostomy tube were randomised to receive either peritubal infiltration or ICNB. At the completion of the procedure, patients in Group P received peritubal infiltration and those in Group I received ICNB at 10, 11, 12^th spaces using fluoroscopy guidance. Postoperatively, patients were followed for 24 h for pain using Visual Analogue Scale (VAS) and Dynamic VAS. Rescue analgesia was inj. tramadol 1 mg/kg IV when pain score exceeded 4. Time to first rescue analgesia, number of doses and patient's satisfaction were noted in all patients.

Results:

Pain scores were lower in the group I at all points of measurement than group P. The mean time to first demand for rescue analgesia was higher in Group I (13.22 ± 4.076 h vs 7.167 ± 3.92 h P - 0.001). The number of demands and the amount of analgesics consumed were less in Group I.

Conclusion:

ICNB provided superior analgesia as evidenced by longer time to first demand of analgesic, reduced number of demands and consumption of rescue analgesic. Peritubal infiltration, although less efficacious, may be a safe and simple alternative technique.

Chemical-Induced Nephropathy: A Review of the Renal Tubulointerstitial Lesions in Humans

It is almost ironic that one of the major organs that serves to maintain the “internal milieux” by secretion of various toxic agents, can itself become injured in the process. The pattern of morphologic renal injury is nonspecific and can involve any of the components of the kidney, although the injury and subsequent morphologic changes are most commonly noted in the tubules and/or interstitium. Of course, unless the drug/toxin is commonly or regularly noted to be associated with tubular and/or interstitial injury, the association of the drug with the renal changes may be missed and the correlation may not necessarily identify causation. For example, if a drug is associated with a renal injury in a given individual, it may be quite difficult to prove that the drug is the cause of the injury. This scenario is somewhat reminiscent of the test question—is it “true-true-related,” or “true-true-unrelated”? Sometimes it is only by the accrual of a great many examples or correlations, and or dissection of the pathophysiology, can it be shown that the drug is directly related to the observed morphologic (and subsequent clinical) injury. Renal changes induced by chemicals can affect the tubules, interstitium or both. This review of chemically induced nephropathy in humans considers acute tubular necrosis, interstitial nephritis , and tubulointerstitial nephritis or nephropathy. Because the tubules and the interstitium are so intimately related, injury to 1 of these 2 components may eventually lead to injury of the other, resulting in tubulointerstitial disease.

Acute renal injury after partial hepatectomy

Currently, partial hepatectomy is the treatment of choice for a wide variety of liver and biliary conditions. Among the possible complications of partial hepatectomy, acute kidney injury (AKI) should be considered as an important cause of increased morbidity and postoperative mortality. Difficulties in the data analysis related to postoperative AKI after liver resections are mainly due to the multiplicity of factors to be considered in the surgical patients, moreover, there is no consensus of the exact definition of AKI after liver resection in the literature, which hampers comparison and analysis of the scarce data published on the subject. Despite this multiplicity of risk factors for postoperative AKI after partial hepatectomy, there are main factors that clearly contribute to its occurrence. First factor relates to large blood losses with renal hypoperfusion during the operation, second factor relates to the occurrence of post-hepatectomy liver failure with consequent distributive circulatory changes and hepatorenal syndrome. Eventually, patients can have more than one factor contributing to post-operative AKI, and frequently these combinations of acute insults can be aggravated by sepsis or exposure to nephrotoxic drugs.

The EP3 receptor regulates water excretion in response to high salt intake

The mechanisms by which prostanoids contribute to the maintenance of whole body water homeostasis are complex and not fully understood. The present study demonstrates that an EP3-dependent feedback mechanism contributes to the regulation of water homeostasis under high-salt conditions. Rats on a normal diet and tap water were placed in metabolic cages and given either sulprostone (20 μg·kg^-1·day^-1) or vehicle for 3 days to activate EP3 receptors in the thick ascending limb (TAL). Treatment was continued for another 3 days in rats given either 1% NaCl in the drinking water or tap water. Sulprostone decreased expression of cyclooxygenase 2 (COX-2) expression by ∼75% in TAL tubules from rats given 1% NaCl concomitant with a ∼60% inhibition of COX-2-dependent PGE₂ levels in the kidney. Urine volume increased after ingestion of 1% NaCl but was reduced ∼40% by sulprostone. In contrast, the highly selective EP3 receptor antagonist L-798106 (100 μg·kg^-1·day^-1), which increased COX-2 expression and renal PGE₂ production, increased urine volume in rats given 1% NaCl. Sulprostone increased expression of aquaporin-2 (AQP2) in the inner medullary collecting duct plasma membrane in association with an increase in phosphorylation at Ser269 and decrease in Ser261 phosphorylation; antagonism of EP3 with L-798106 reduced AQP2 expression. Thus, although acute activation of EP3 by PGE₂ in the TAL and collecting duct inhibits the Na-K-2Cl cotransporter and AQP2 activity, respectively, chronic activation of EP3 in vivo limits the extent of COX-2-derived PGE₂ synthesis, thereby mitigating the inhibitory effects of PGE₂ on these transporters and decreasing urine volume.

Role of buprenorphine in prolonging the duration of post-operative analgesia in percutaneous nephrolithotomy: Comparison between bupivacaine versus bupivacaine and buprenorphine combination

Introduction:

Percutaneous nephrolithotomy (PCNL) is the treatment of choice for large renal calculi. Pain around the nephrostomy tube is a clinical problem and we have previously reported alleviation of pain by peritubal block with bupivacaine, which lasted for 14 hours. The present study aimed to investigate the role of buprenorphine and bupivacaine combination in prolonging the duration of analgesia in peritubal block.

Materials and Methods:

A prospective, randomized controlled study was undertaken in 40 American Society of Anesthesiologists (ASA) grade I and II patients who were scheduled for PCNL. Group I patients received 20 mL of 0.25% bupivacaine and group II patients received 20 mL of 0.25% bupivacaine with 100 μg of buprenorphine. Peritubal infiltration was given under fluoroscopic guidance along the nephrostomy tube from the renal capsule to the skin. Post-operative pain was assessed by Visual Analog Score (VAS), dynamic VAS (DVAS), sedation score, duration of analgesia and number of rescue analgesic demands. Rescue analgesia was inj tramadol 1 mg/kg IV if pain score exceeded 3.

Results:

Demographic data were comparable between the groups. Median duration of analgesia was 16 h in group I and 20 h in group II (P = 0.002). The maximum median VAS was 4 in group I and 2 in group II (P = 0.002). The median area under curve (AUC) for VAS was 7 and 5 in groups I and II, respectively (P = 0.047). The median maximum DVAS in group I was 6 and 4 in group II. The median AUC for DVAS in 24 h was 16 in group I and 15 in group II (P = 0.017).

Conclusions:

Peritubal infiltration of 0.25% bupivacaine with 100 μg buprenorphine around a nephrostomy tube increased the duration of analgesia following PCNL without any side-effects.

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.

Indomethacin, amiloride, or eplerenone for treating hypokalemia in Gitelman syndrome

Patients with Gitelman syndrome (GS), an inherited salt-losing tubulopathy, are usually treated with potassium-sparing diuretics or nonsteroidal anti-inflammatory drugs and oral potassium and magnesium supplementations. However, evidence supporting these treatment options is limited to case series studies. We designed an open-label, randomized, crossover study with blind end point evaluation to compare the efficacy and safety of 6-week treatments with one time daily 75 mg slow-release indomethacin, 150 mg eplerenone, or 20 mg amiloride added to constant potassium and magnesium supplementation in 30 patients with GS (individual participation: 48 weeks). Baseline plasma potassium concentration was 2.8±0.4 mmol/L and increased by 0.38 mmol/L (95% confidence interval [95% CI], 0.23 to 0.53; P<0.001) with indomethacin, 0.15 mmol/L (95% CI, 0.02 to 0.29; P=0.03) with eplerenone, and 0.19 mmol/L (95% CI, 0.05 to 0.33; P<0.01) with amiloride. Fifteen patients became normokalemic: six with indomethacin, three with eplerenone, and six with amiloride. Indomethacin significantly reduced eGFR and plasma renin concentration. Eplerenone and amiloride each increased plasma aldosterone by 3-fold and renin concentration slightly but did not significantly change eGFR. BP did not significantly change. Eight patients discontinued treatment early because of gastrointestinal intolerance to indomethacin (six patients) and hypotension with eplerenone (two patients). In conclusion, each drug increases plasma potassium concentration in patients with GS. Indomethacin was the most effective but can cause gastrointestinal intolerance and decreased eGFR. Amiloride and eplerenone have similar but lower efficacies and increase sodium depletion. The benefit/risk ratio of each drug should be carefully evaluated for each patient.

Renal effects induced by prolonged mPGES1 inhibition

The importance of membrane-bound PGE synthase 1 (mPGES1) in the regulation of renal function has been examined in mPGES1-deficient mice or by evaluating changes in its expression. However, it is unknown whether prolonged mPGES1 inhibition induces significant changes of renal function when Na+ intake is normal or low. This study examined the renal effects elicited by a selective mPGES1 inhibitor (PF-458) during 7 days in conscious chronically instrumented dogs with normal Na+ intake (NSI) or low Na+ intake (LSI). Results obtained in both in vitro and in vivo studies have strongly suggested that PF-458 is a selective mPGES1 inhibitor. The administration of 2.4 mg·kg−1·day−1 PF-458 to dogs with LSI did not induce significant changes in renal blood flow (RBF) and glomerular filtration rate (GFR). A larger dose of PF-458 (9.6 mg·kg−1·day−1) reduced RBF ( P < 0.05) but not GFR in dogs with LSI and did not induce changes of renal hemodynamic in dogs with NSI. Both doses of PF-458 elicited a decrease ( P < 0.05) in PGE2 and an increase ( P < 0.05) in 6-keto-PGF1α. The administration of PF-458 did not induce significant changes in renal excretory function, plasma renin activity, and plasma aldosterone and thromboxane B2 concentrations in dogs with LSI or NSI. The results obtained suggest that mPGES1 is involved in the regulation of RBF when Na+ intake is low and that the renal effects elicited by mPGES1 inhibition are modulated by a compensatory increment in PGI2. These results may have some therapeutical implications since it has been shown that prolonged mPGES1 inhibition has lower renal effects than those elicited by nonsteroidal anti-inflammatory drugs or selective cyclooxygenase-2 inhibitors.

Nephrotic-range proteinuria and interstitial nephritis associated with the use of a topical loxoprofen patch

A 76-year-old woman with a history of lumbar fracture and marked proteinuria, bilateral pitting edema, malaise and pruritus was referred for an evaluation of an impaired renal function. A renal biopsy led to a tentative diagnosis of acute interstitial nephritis (AIN) with minimal change disease caused by nonsteroidal anti-inflammatory drugs (NSAIDs). Following the discontinuation of oral NSAIDs, the patient's symptoms disappeared spontaneously. However, nephrotic-range proteinuria relapsed one month after discharge, following loxoprofen patch use. The withdrawal of the topical loxoprofen patches once again resulted in the disappearance of all symptoms. This is the first case report of nephrotic-range proteinuria and AIN secondary to topical NSAID patch use.

Cyclooxygenase metabolites in the kidney

In the mammalian kidney, prostaglandins (PGs) are important mediators of physiologic processes, including modulation of vascular tone and salt and water. PGs arise from enzymatic metabolism of free arachidonic acid (AA), which is cleaved from membrane phospholipids by phospholipase A2 activity. The cyclooxygenase (COX) enzyme system is a major pathway for metabolism of AA in the kidney. COX are the enzymes responsible for the initial conversion of AA to PGG2 and subsequently to PGH2, which serves as the precursor for subsequent metabolism by PG and thromboxane synthases. In addition to high levels of expression of the "constitutive" rate-limiting enzyme responsible for prostanoid production, COX-1, the "inducible" isoform of cyclooxygenase, COX-2, is also constitutively expressed in the kidney and is highly regulated in response to alterations in intravascular volume. PGs and thromboxane A2 exert their biological functions predominantly through activation of specific 7-transmembrane G-protein-coupled receptors. COX metabolites have been shown to exert important physiologic functions in maintenance of renal blood flow, mediation of renin release and regulation of sodium excretion. In addition to physiologic regulation of prostanoid production in the kidney, increases in prostanoid production are also seen in a variety of inflammatory renal injuries, and COX metabolites may serve as mediators of inflammatory injury in renal disease.

Leukotrienes, but not angiotensin II, are involved in the renal effects elicited by the prolonged cyclooxygenase-2 inhibition when sodium intake is low

It is known that cyclooxygenase-2 (COX-2) inhibition elicits significant renal hemodynamics alterations when sodium intake is low. However, the mechanisms involved in these renal changes are not well known. Our objective was to evaluate the role of angiotensin II and 5-lipooxygenase-derived metabolites in the renal effects induced by prolonged COX-2 inhibition when sodium intake is low. Conscious dogs were treated during 7 days with a COX-2 inhibitor (1 mg·kg·d, SC75416), and either a vehicle, an AT1 receptor antagonist (0.4 mg · kg · d, candesartan) or a selective 5-lipooxygenase inhibitor (PF-150, 20 and 60 mg · kg · d). The administration of SC75416 alone induced significant changes in renal blood flow (219 ± 14 to 160 ± 10 mL/min), glomerular filtration rate (51 ± 2 to 42 ± 3 mL/min), and plasma potassium (pK) (4.3 ± 0.1 to 4.6 ± 0.1 mEq/L). Similar decrements in renal blood flow (27%) and glomerular filtration rate (20%) and a similar increment in pK (7%) were found when SC75416 was administered in candesartan-pretreated dogs. However, SC75416 administration did not elicit significant changes in renal hemodynamics and pK in dogs pretreated with each dose of PF-150. Our data suggest that leukotrienes but not angiotensin II are involved in the renal effects induced by COX-2 inhibition when sodium intake is low.

Effect of ultrasound-guided intercostal nerve block on postoperative pain after percutaneous nephrolithotomy : prospective randomized controlled study

BACKGROUND

The aim of the study was to investigate the effect of preoperative ultrasound-guided (US) intercostal nerve block (ICNB) in the 11th and 12th intercostal spaces on postoperative pain control and tramadol consumption in patients undergoing percutaneous nephrolithotomy (PCNL).

METHODS

After obtaining ethical committee approval and written informed patient consent, 40 patients were randomly allocated to the ICNB group or the control group. For the ICNB group US-guided ICNB was performed with 0.5 % bupivacaine and 1/200,000 epinephrine at the 11th and 12th intercostal spaces after premedication. A sham block was performed for the control group and postoperative pain and tramadol consumption were recorded by anesthesiologists blinded to the treatment.

RESULTS

Postoperative visual analog scale scores at all follow-up times were found to be significantly lower in the ICNB group than in the control group (p < 0.05). The mean 24 h intravenous tramadol consumption was 97.5 ± 39.5 mg for the ICNB group which was significantly lower than the 199.7 ± 77.6 mg recorded for the control group (p < 0.05).

CONCLUSION

In PCNL with nephrostomy tube placement US-guided ICNB performed at the 11th and 12th intercostal spaces provided effective analgesia.

Analgesic efficacy of peritubal infiltration of ropivacaine versus ropivacaine and morphine in percutaneous nephrolithotomy under ultrasonic guidance

Background and Purpose:

Percutaneous nephrolithotomy is a safe and effective endourologic procedure which is less morbid than open surgery. However, pain around a nephrostomy tube requires good post-operative analgesia. We hypothesize that infiltration of local anesthetic with opioid from the renal capsule to the skin around the nephrostomy tract under ultrasonic guidance would alleviate the postoperative pain for a long period.

Methods:

A total of 60 ASA physical status I to II patients were selected for a prospective randomized double-blind controlled study in percutaneous nephrolithotomy surgeries. Patients were divided into group R (n=30) and group RM (n=30). Balanced general anesthesia was given. After completion of the surgical procedure, a 23-gauze spinal needle was inserted at 6 and 12 O’clock position under ultrasonic guidance up to renal capsule along the nephrostomy tube. A 10 ml drug solution was infiltrated in each tract while withdrawing from renal capsule to the skin. After extubation, the patient was shifted to the post-anesthesia care unit for 24 hours. Post-operative pain was assessed using the visual analog scale (VAS) and dynamic visual analog scale (DVAS) (during deep breathing and coughing) rating 0-10 for initial 24 hours. Rescue analgesia was given in the form of injection tramadol 1.0 mg/kg intravenously when VAS ≥4 and maximum up to 400 mg in 24 hours. Time to 1^st rescue analgesic, number of doses of tramadol and total consumption of tramadol required in initial 24 hours were noted. Patients were observed for any side effect and treated accordingly.

Results:

Time to 1^st rescue analgesic, i.e., duration of analgesia in group RM is more prolonged than group R (P=0.0004). The number of doses of tramadol in 24 hours in group R were higher as compared to group RM (P=0.0003). The total amount of tramadol in 24 hours in group R was more than in group RM (P=0.0013). Side effects like nausea and vomiting and sedation were comparable in both the groups.

Conclusion:

Addition of morphine to ropivacaine for nephrostomy tract infiltration significantly prolonged the duration of post-operative analgesia and reduced the number of doses and total consumption of rescue analgesic in initial 24 hours in percutaneous nephrolithotomy surgery.

Comparison of gastroduodenal ulcer incidence in healthy Japanese subjects taking celecoxib or loxoprofen evaluated by endoscopy: a placebo-controlled, double-blind 2-week study

BACKGROUND

Although nonsteroidal anti-inflammatory drugs (NSAIDs) are widely prescribed globally, their chronic use increases the risk of upper gastrointestinal (GI) damage. Cyclooxygenase-2-selective NSAIDs are considered to reduce this risk. Current guidelines in Japan recommend loxoprofen sodium (loxoprofen), a pro-drug in the propionic acid class of nonselective NSAIDs, as first-line therapy in rheumatoid arthritis.

AIM

To confirm the superiority of celecoxib, a cyclooxygenase-2-selective NSAID, to loxoprofen in the incidence of gastroduodenal (GD) endoscopic ulcers.

METHODS

A randomised, multicentre, placebo-controlled, double-blind, phase IV clinical trial in healthy Japanese volunteers [mean age 57.5 (range: 40-74) years; >70% female], stratified by Helicobacter pylori status at screening (~40% positive) and randomised 2:2:1 to receive celecoxib 100 mg b.d., loxoprofen 60 mg t.d.s. or placebo. Primary end point was incidence of any GD endoscopic ulcers after 2 weeks of treatment.

RESULTS

Of 190 randomised subjects, 189 received at least one dose of celecoxib (n = 76), loxoprofen (n = 76), or placebo (n = 37). Incidence of GD ulcers was 1.4%, 27.6% and 2.7% in the celecoxib, loxoprofen and placebo groups respectively (P < 0.0001 in favour of the celecoxib group); incidence of adverse events (AEs) was 34.2%, 51.3% and 21.6% in the celecoxib, loxoprofen and placebo groups respectively. No serious or severe AEs were reported.

CONCLUSIONS

Celecoxib 100 mg b.d. was superior to loxoprofen 60 mg t.d.s. regarding the incidence of gastro-duodenal endoscopic ulcers over 2 weeks. Celecoxib was well tolerated and no major safety concerns were observed.

Non-steroidal anti-inflammatory treatment in cancer cachexia: a systematic literature review

BACKGROUND

There are no established treatments for cachexia. Recently it has been suggested that the evidence for non-steroidal anti-inflammatory (NSAID) treatment is sufficient to support its regular clinical use. Primary objective in this systematic review was to assess efficacy and safety of NSAID treatment in improving body weight and muscle mass in patients with cancer cachexia. Secondary objectives were to assess whether this treatment could improve other cachexia domains such as anorexia and food intake, catabolic drive and function.

MATERIAL AND METHODS

A systematic literature review of PubMed, EMBASE and Cochrane Central register of controlled trials database was carried out using both text words and MeSH/EMTREE terms.

RESULTS

Thirteen studies were included; all but two trials showed either improvement or stabilization in weight or lean body mass. Seven studies were without a comparator. Studies are generally small and a few are methodologically flawed, often due to multiple outcomes with excess risk of false positives.

CONCLUSION

NSAIDs may improve weight in cancer patients with cachexia, and there is some evidence on effect on physical performance, self-reported quality of life and inflammatory parameters. Evidence is too frail to recommend NSAID for cachexia outside clinical trials. This is supported by the known side effects of NSAIDs, even though the reviewed literature report almost negligible toxicity.

Drug-induced life-threatening potassium disturbances detected by a pharmacovigilance program from laboratory signals

PURPOSE

Detection and reporting of drug-induced life-threatening potassium disturbances and the study of associated factors under a Pharmacovigilance Program using Laboratory Signals at a Hospital (PPLSH) during a 2-year period.

METHODS

All serum potassium levels <2 mmol/l or >7 mmol/l detected at admission to the hospital, including those of patients who died in the emergency ward or during hospitalization, were monitored prospectively from January 2009 through to December 2010. The incidence rate of each etiology of potassium disturbances was calculated. Factors associated with drug-induced potassium disturbances were detected using a multiple logistic regression model.

RESULTS

The incidence of true life-threatening drug-induced hyper- and hypokalemia events was 3 and 4.32 (Poisson 95 % confidence interval 1.62-10.24), respectively, per 10,000 admissions. Of the severe potassium disturbances, 32.3 % were drug-induced, and 23 % were lethal. We identified previously undescribed pharmacological causes of hyperkalemia (risedronate, doxazosin) and hypokalemia (acyclovir, teicoplanin, cefepime, meropenem, dexketoprofen colistimethate). Significant predictor factors associated with drug-induced hyperkalemia were the use of polypharmacy (>5 drugs), age (>74 years), sex (female) and kidney disease (glomerular filtration rate <60 ml/min) with the presence of ≥4 comorbid conditions. The only predictor of drug-induced hypokalemia was the use of >5 drugs. The triggering factor associated with drug-induced hyperkalemia and hypokalemia was azotemia and hypoalbuminemia, respectively.

CONCLUSIONS

Drug-induced life-threatening potassium disturbances remain a relevant problem. Potential strategies for prevention are to avoid polypharmacy, early discontinuation of treatment of drugs causing hyperkalemia or nephrotoxicity in cases of various clinical situations (cardiac descompensation, infection, hypovolemia) or obstructive causes, and insistence on albumin control during hospitalization.

Prostaglandin E2 EP3 receptor regulates cyclooxygenase-2 expression in the kidney

Cyclooxygenase-2 (COX-2) is constitutively expressed and highly regulated in the thick ascending limb (TAL). As COX-2 inhibitors (Coxibs) increase COX-2 expression, we tested the hypothesis that a negative feedback mechanism involving PGE(2) EP3 receptors regulates COX-2 expression in the TAL. Sprague-Dawley rats were treated with a Coxib [celecoxib (20 mg·kg(-1)·day(-1)) or rofecoxib (10 mg·kg(-1)·day(-1))], with or without sulprostone (20 μg·kg(-1)·day(-1)). Sulprostone was given using two protocols, namely, previous to Coxib treatment (prevention effect; Sulp7-Coxib5 group) and 5 days after initiation of Coxib treatment (regression effect; Coxib10-Sulp5 group). Immunohistochemical and morphometric analysis revealed that the stained area for COX-2-positive TAL cells (μm(2)/field) increased in Coxib-treated rats (Sham: 412 ± 56.3, Coxib: 794 ± 153.3). The Coxib effect was inhibited when sulprostone was used in either the prevention (285 ± 56.9) or regression (345 ± 51.1) protocols. Western blot analysis revealed a 2.1 ± 0.3-fold increase in COX-2 protein expression in the Coxib-treated group, an effect abolished by sulprostone using either the prevention (1.2 ± 0.3-fold) or regression (0.6 ± 0.4-fold vs. control, P < 0.05) protocols. Similarly, the 6.4 ± 0.6-fold increase in COX-2 mRNA abundance induced by Coxibs (P < 0.05) was inhibited by sulprostone; prevention: 0.9 ± 0.3-fold (P < 0.05) and regression: 0.6 ± 0.1 (P < 0.05). Administration of a selective EP3 receptor antagonist, L-798106, also increased the area for COX-2-stained cells, COX-2 mRNA accumulation, and protein expression in the TAL. Collectively, the data suggest that COX-2 levels are regulated by a novel negative feedback loop mediated by PGE(2) acting on its EP3 receptor in the TAL.