Analgesic nephropathy: etiology, clinical syndrome, and clinicopathologic correlations in Australia

Renal Papillary Necrosis (RPN) in an African Population: Disease Patterns, Relevant Pathways, and Management

Renal papillary necrosis (RPN) is characterized by coagulative necrosis of the renal medullary pyramids and papillae. Multiple conditions and toxins are associated with RPN. Several RPN risk factors, or POSTCARDS, have been identified, with most patients presenting with RPN having at least two contributing risk factors. Currently, there is no specific test to diagnose and confirm RPN; however, several imaging tools can be used to diagnose the condition. RPN is currently underdiagnosed in African populations, often with fatal outcomes. In African clinical settings, there is a lack of consensus on how to define and describe RPN in terms of kidney anatomy, pathology, endourology, epidemiology, the identification of African-specific risk factors, the contribution of oxidative stress, and lastly an algorithm for managing the condition. Several risk factors are unique to African populations including population-specific genetic factors, iatrogenic factors, viral infections, antimicrobial therapy, schistosomiasis, substance abuse, and hypertension (GIVASSH). Oxidative stress is central to both GIVASSH and POSTCARDS-associated risk factors. In this review, we present information specific to African populations that can be used to establish an updated consensual definition and practical grading system for radiologists, urologists, nephrologists, nuclear physicians, and pathologists in African clinical settings.

Toxic nephropathy: Adverse renal effects caused by drugs

This is a brief overview of toxic nephropathy, which is an increasingly recognised problem with the continual introduction of new drugs and novel drug modalities, especially in oncology, and the risks associated with polypharmacy in many patients; although it is important to remember that it may not always be caused by a drug. It is also important to note that several possibly harmful drugs are now available without prescription ('over-the-counter') and can be purchased easily over the internet, including some poorly characterised herbal remedies. Knowing exactly what our patients are taking as medication is not always easy and patients often fail to mention drugs that may not have been prescribed by a doctor or recommended by a pharmacist. Moreover, patients with several comorbidities often require care from more than one doctor in other specialties, which can also lead to drug prescribing in isolation. This article will summarise some key aspects of drug nephrotoxicity and provide a few clinical pointers to consider, bearing in mind that there is rarely any antidote available, and effective treatment relies on early detection, prompt drug withdrawal, and supportive care. This short review is intended only as a primer to highlight some of the more practical aspects of toxic nephropathy; its content is based on a lecture delivered during the 2021 European Congress of Internal Medicine.

"Recurrent Papillary Necrosis and Nephrocalcinosis Induced by Nonsteroidal Anti-Inflammatory Drugs for Gouty Arthritis Associated with Congenital Chloride-Losing Diarrhea: A Major Risk for Kidney Loss"

Congenital chloride-losing diarrhea (CCLD) is a rare genetic disorder due to autosomal recessive mutation in the SLC26A3 gene on chromosome 7. It is characterized with chronic watery diarrhea with high fecal chloride (Cl: >90 mmol/L), low potassium (K), and metabolic alkalosis with low urinary Cl and K. The overall long-term prognosis is favorable with optimal life-long salt and K supplementation. In this case report, we describe a man with progressive renal failure and small kidneys that showed nephrocalcinosis and papillary necrosis. His disease was diagnosed since birth and was confirmed by our tests. He was incompliant with therapy and had developed gout. The latter complication of his disease has led to excessive NSAID use over the past years. Reinstitution of diet, drug therapy, and allopurinol had stabilized his renal disease for 1 year of follow-up. In conclusion, excessive analgesic use is a risk factor for renal failure in CCLD.

The case for cautious consumption: NSAIDs in chronic kidney disease

PURPOSE OF REVIEW

Strong epidemiological and pathologic evidence associates NSAIDs with kidney disease, both acute and chronic. Hence, the usage of NSAIDs has decreased in patients with, or at risk for, chronic kidney disease (CKD). Coupled with this has been a rise in use of opioids and other non-NSAID alternatives, which do come with significant, and underrecognized, risk of nonrenal adverse events. We review the literature to understand if this shift is appropriate or deleterious.

RECENT FINDINGS

NSAIDs do have a low but tangible risk in causing acute kidney injury, electrolyte imbalances, and increasing blood pressure. However, their role in causing progressive kidney disease is due to long-term usage in high cumulative dosages, and the use of NSAIDs in combination with other agents. Alternatives such as opioids, tramadol, gabapentin and baclofen have weak evidence to support their use and strong evidence to show their harm in patients with CKD.

SUMMARY

Tradeoffs are inherent in using active pharmaceuticals, and NSAIDs are no exception. Balancing potential benefits with possible adverse effects around pain management should be a part of every conversation for patients with kidney disease.

Paracetamol and analgesic nephropathy: Are you kidneying me?

INTRODUCTION

Analgesic nephropathy is a disease resulting from the frequent use of combinations of analgesic medications over many years, leading to significant impairment of renal function. The observation of a large number of cases of renal failure in patients abusing analgesic mixtures containing phenacetin led to the initial recognition of the nephrotoxicity from the use of analgesics. Phenacetin was subsequently exclusively blamed for this disease. However, the role of a single analgesic as a sole cause of analgesic nephropathy was challenged, and a number of researchers have since attempted to determine the extent of involvement of other analgesics including nonsteroidal anti-inflammatory drugs (NSAIDs), aspirin, and paracetamol.

CASE PRESENTATION

We present the case of an 83-year-old woman with a history of NSAID-induced nephropathy with poor pain control and reluctance to use paracetamol. We attempt to briefly review the evidence of paracetamol being implicated in the development of analgesic-induced nephropathy.

CONCLUSION

There is a lack of concrete data regarding causative analgesics, including paracetamol. Patients should therefore not be withheld paracetamol, an effective and commonly recommended agent, for fear of worsening renal function.

Development and results of a kidney disease knowledge survey given to patients with CKD

BACKGROUND

Little is known about disease-specific knowledge in patients with chronic kidney disease (CKD). We developed and examined the results of a survey to characterize kidney disease knowledge.

DESIGN

Survey about kidney disease knowledge, with questions developed by experts.

SETTING & PARTICIPANTS

401 adult patients with CKD (stages 1-5) attending a nephrology clinic from April-October 2009.

OUTCOMES & MEASUREMENTS

We calculated survey reliability using the Kuder-Richardson-20 coefficient and established construct validity by testing a priori hypotheses of associations between survey results and patient characteristics. We descriptively analyzed survey responses and applied linear regression analyses to evaluate associations with patient characteristics. Health literacy was measured using the Rapid Estimate of Adult Literacy in Medicine.

RESULTS

Participants' median age was 58 (25th-75th percentile, 46-68) years, 83% were white, 18% had limited literacy, and 77% had CKD stages 3-5. The 28-question knowledge survey had good reliability (Kuder-Richardson-20 coefficient = 0.72), and mean knowledge score was 66% ± 15% (SD). In support of the construct validity of our knowledge survey, bivariate analysis shows that scores were associated with age (β = -0.01/10 years; 95% CI, -0.02 to -0.005; P = 0.003), formal education (β = 0.09; 95% CI, 0.03-0.15; P = 0.004), health literacy (β = 0.06; 95% CI, 0.03-0.10; P = 0.001), kidney education class participation (β = 0.05; 95% CI, 0.01-0.09; P = 0.009), knowing someone else with CKD (β = 0.05; 95% CI, 0.02-0.08; P = 0.001), and awareness of one's own CKD diagnosis (β = 0.07; 95% CI, 0.04-0.10; P < 0.001). Findings were similar in adjusted analyses.

LIMITATIONS

Recruitment from 1 clinic limits generalizability of findings.

CONCLUSIONS

For patients with CKD, this Kidney Knowledge Survey (KiKS) is reliable and valid and identifies areas of and risk factors for poor kidney knowledge. Further study is needed to determine the impact of CKD knowledge on self-care behaviors and clinical outcomes.

Changes of panorama in renal disease mortality in Finland after phenacetin restriction

The purpose of the present study was to examine the effect of phenacetin consumption and its restriction on the mortality from nephropathy. Changes in this mortality in Finland during 1951-77 were investigated. The second part of the study was concerned with the frequency of papillary necrosis in cases autopsied in the Department of Medicine, Turku University Central Hospital, during 1952-79. These figures were studied in relation to increased phenacetin consumption after World War II, its restriction in 1962 and its complete banning in 1965. Both the epidemiologic survey of the mortality from nephropathy in Finland and the autopsies showed a clear and strong correlation both with increased phenacetin consumption and with its discontinuation. The banning of phenacetin led within 2-4 years to a decline in the mortality from nephropathy to its pre-phenacetin level.

The effect of low-protein diet supplemented with ketoacids in patients with chronic renal failure

Ismert, hogy az étrendi fehérjemegszorítás lassítja a krónikus vesebetegség progresszióját. Ha a fehérjebevitel kevesebb mint 0,5-0,6 g/ttkg/nap, a diétát esszenciális aminosavakkal/ketosavakkal szükséges kiegészíteni. A szerzők tanulmányukban a hosszú időn keresztül ketosavakkal kiegészített fehérjeszegény diéta hatását vizsgálták krónikus veseelégtelenségben szenvedő betegekben a veseelégtelenség progressziójára, a kalcium- és foszforanyagcserére, a betegek tápláltsági állapotára, továbbá felmérték a betegek complience-ét. Ötvenegy beteget kezeltek 12–57 hónapig (átlagos kezelési idő: 26 hónap). A szérumkreatinin-érték átlaga 349,72±78,04 µmol/l-ről 460,66±206,66 µmol/l-re emelkedett, amely 27 µmol/l/év, illetve 2,3 µmol/l/hó szérumkreatinin-növekedést jelentett. A Cockroft–Gault-formula alapján számolt glomerulusfiltrációs ráta (GFR) 21,52±7,84 ml/min-ról 18,22±7,76 ml/min-ra csökkent, ami 0,83 ml/min/év, illetve 0,07 ml/min/hó GFR-csökkenést jelentett. Lineáris regressziós analízissel az 1/szérumkreatinin versus időegyenes dőlésszöge 0,0018 volt. A szérumparathormon-szint szignifikánsan csökkent, a szérumkalcium, -foszfor szintje nem változott. A betegek tápláltsági állapota (a BMI, szérumalbumin, szubjektív tápláltsági felmérés alapján) a folyamatos és intenzív diétás edukációnak köszönhetően nem romlott, a betegek tartani tudták az alacsony fehérjetartalmú diétát a kezelés hosszú időtartama alatt. Eredményeik igazolják, hogy a ketosavakkal kiegészített fehérjeszegény diéta hatásos a veseelégtelenség progressziójának csökkentésében, előnyösen befolyásolja a kalcium- és foszforanyagcserét, nem rontja a betegek tápláltsági állapotát.

Analgesic nephropathy and renal replacement therapy in Australia: trends, comorbidities and outcomes

BACKGROUND AND OBJECTIVES

This study examined age-specific incidence and prevalence of renal replacement therapy attributed to analgesic nephropathy from 1971 through 2005 and adjusted comorbidity prevalence and survival of patients who had analgesic nephropathy and were on renal replacement therapy (compared with control subjects without diabetes).

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This retrospective cohort study, using data from the Australia and New Zealand Dialysis and Transplant registry, included all patients who were aged 35 to 84 yr and started long-term renal replacement therapy in Australia from 1971 through 2006.

RESULTS

Of 31,654 incident renal replacement therapy patients, 10.2% had analgesic nephropathy. Incidence and prevalence of renal replacement therapy attributed to analgesic nephropathy decreased earlier and faster among younger (age <55 yr) patients. Prevalence of analgesic nephropathy among 75- to 84-yr-old renal replacement therapy patients is still increasing. Compared with control subjects without diabetes, comorbidities (coronary artery, cerebrovascular, peripheral vascular, and chronic lung diseases) were more prevalent among patients with analgesic nephropathy at renal replacement therapy start. All-cause, cardiovascular, infection, and cancer mortality were higher among patients who had analgesic nephropathy and were on renal replacement therapy. For both comorbidities and mortality, the associations were stronger in younger patients.

CONCLUSIONS

Trends in renal replacement therapy attributed to analgesic nephropathy differed by age. Patients with analgesic nephropathy have more comorbidities and poorer survival on renal replacement therapy, especially among younger patients.

Drug-associated renal dysfunction and injury

Renal dysfunction and injury secondary to medications are common, and can present as subtle injury and/or overt renal failure. Some drugs perturb renal perfusion and induce loss of filtration capacity. Others directly injure vascular, tubular, glomerular and interstitial cells, such that specific loss of renal function leads to clinical findings, including microangiopathy, Fanconi syndrome, acute tubular necrosis, acute interstitial nephritis, nephrotic syndrome, obstruction, nephrogenic diabetes insipidus, electrolyte abnormalities and chronic renal failure. Understanding the mechanisms involved, and recognizing the clinical presentations of renal dysfunction arising from use of commonly prescribed medications, are important if injury is to be detected early and prevented. This article reviews the clinical features and basic processes underlying renal injury related to the use of common drugs.

Caffeine as a promoter of analgesic-associated nephropathy--where is the evidence?

Individual groups of nephrologists - in their responsibility for their patients - initiated a most controversial discussion whether or not caffeine - coformulated to analgesics - might initiate or sustain analgesic overdosing. The original sources (data) of such suspicion have got lost during the debate of the last two decades. Therefore, it seemed to be appropriate to investigate the original data background and the reasons why nephrologists started to suspect caffeine as a stimulant of analgesic overdosing by employing a systematic and exhaustive review of primary nephrological publications. Their selection followed a precise selection plan, including all epidemiological studies on analgesic-associated nephropathy, the original papers of all groups having been involved in those studies, further originals from the mainly involved countries (academically, politically), and any literature thereof cited as a proof. The following results emerged from the investigation: (i) The epidemiological studies warranted no conclusion about a role of caffeine in prompting excessive analgesic use. (ii) The identified groups of nephrologists provided not substantial data to advocate the said suspicion, except for the observation of a preferential choice of phenacetin-containing combinations, especially powder preparations. (iii) Only two cited original data sources revealed drug-seeking behaviour with phenacetin-containing preparations which subsided, after phenacetin was banned from the respective markets. Conclusively, it appears that there is no substantial data to support a pivotal role of caffeine in initiating or sustaining analgesic overdosing. However, there is strong data that phenacetin, by its psychotropic properties, may have caused drug-seeking behaviour and thus led to analgesic overdosing. This conclusion is convincingly supported by thorough pharmacokinetic investigations. Note: All caffeine-related statements within the reviewed literature have been collected in tables (referred to as Table SX) which are provided in full text for check on the following website: http://www.blackwellpublishing.com/products/journals/suppmat/FCP/FCP174/FCP174sm.htm

Trends of analgesic nephropathy in two high-endemic regions with different legislation

Analgesic abuse is related to a specific form of interstitial nephritis, but the exact nature of the causal agent remains controversial and this has resulted in differences in regulation. In Flanders, the free sale of phenacetin was banned, but the consumption of other combined analgesics remained free. In New South Wales, phenacetin was also banned, but 2 yr later the sales of all combined analgesics were also prohibited. This study compared the evolution of end-stage renal disease as a result of analgesic nephropathy (AN) in these two high-endemic regions with different legislation. In both regions, the time trend of the age-specific incidence of end-stage renal disease as a result of AN is similar in the age group 45 to 54 yr. In all age groups combined, the time trend of the percentage of AN among the patients admitted for renal replacement therapy is also similar. This finding does not support the hypothesis that non-phenacetin mixed analgesics play a significant role in the occurrence of AN.

Analgesic nephropathy in rodents

While it is clear that humans suffer from "classic" analgesic nephropathy, the causative agents and mechanisms are still not known. A review of the literature revealed that chronic acetaminophen exposure does not produce renal papillary necrosis in rodents or humans. In contrast, while chronic aspirin exposure to rodents results in renal papillary necrosis with renal morphological and functional changes similar to that described in humans, epidemiological studies do not implicate aspirin alone in human analgesic nephropathy. The difference in the effects of aspirin in humans and rats may be due to the inability of epidemiological studies to detect aspirin-induced analgesic nephropathy or more likely to the fact that species differences exist, with the rat being more sensitive than humans. With respect to combinations of aspirin and acetaminophen, with or without caffeine, there are minimal tightly controlled studies. In addition, there is little evidence of enhanced renal papillary necrosis in rodents treated with aspirin and acetaminophen combinations. In summary, it remains to be determined what chemical entities cause "classic" analgesic nephropathy in humans and the mechanisms of this toxicity such that preventative measures can be instituted. Elucidation of the mechanisms of analgesic nephropathy has been hampered due to the lack of animal models that closely mimic the human disease. Rodents do not appear to be an appropriate model.

Drug-induced nephrotoxicity

Drug-induced renal dysfunction is not an uncommon event, which can cause significant morbidity and can be easily overlooked. Many medications can lead to renal dysfunction through various mechanisms. The most common medications or classes of medications along with their clinical presentations are discussed in this article. As can be noted, many drugs can cause nephropathy in more than one way. Because it is difficult to discuss nephrotoxicities of every reported medication, Tables 1, 2, and 3 are provided; although these tables are by no means comprehensive, they may serve as further reference. This article is intended to provide a broad overview of the spectrum of presentation associated with drug-induced nephrotoxicity to guide the clinician to familiarity with this entity.

Investigation of regional glutathione levels in a model of chemically-induced renal papillary necrosis

The effect of diphenylamine on renal cortical, outer medullary and inner medullary glutathione (GSH) concentrations and the effect of GSH depletion on the nephrotoxicity of diphenylamine were investigated in male Syrian hamsters. A dose-dependent decrease in renal cortical GSH was observed within 1 hr of a single oral dose of diphenylamine (200, 400 or 600 mg/kg body weight), but statistically significant changes in outer medullary or papillary GSH were not observed. Reduction of renal papillary GSH to 29% of basal concentration [by prior treatment with L-buthionine sulfoxime (500 mg/kg body weight, ip)] did not increase the papillotoxicity of a non-toxic dose of diphenylamine (400 mg/kg) administered orally. The findings indicate that diphenylamine-induced renal papillary necrosis in the Syrian hamster is not associated with a decrease in renal papillary or outer medullary GSH nor mediated by oxidative cell injury.

Nephrotoxicity of xenobiotics

Nephrotoxicity can be grouped by the xenobiotics place of action, by the clinical presentation or by the generic toxic effect. The latter can be dose related, indirect, idiosyncratic or allergic. Nephrotoxicity of lithium, demeclocycline, aminoglycosides, cyclosporine, mercuric ion, nonsteroidal anti-inflammatory drugs, methoxyflurane, ethylene glycol, D-penicillamine and methicillin is reviewed in light of all these three viewpoints, but emphasis is on toxic mechanisms.

Chronic renal disease and papillary necrosis associated with the long-term use of nonsteroidal anti-inflammatory drugs as the sole or predominant analgesic

The risk of renal papillary necrosis and renal dysfunction due to the chronic use of nonsteroidal anti-inflammatory drugs (NSAIDs) is unknown. In a prospective study of 259 heavy analgesic users seen in a general medical hospital over an 11-year-period beginning in January 1982, 69 new cases of analgesic nephropathy with renal papillary necrosis were confirmed by intravenous urogram (26.6%), ultrasonography (30.4%), and/or computed tomography (43%). Twenty-nine of these patients (42%) had consumed excessive quantities of NSAIDs alone; an additional nine patients (13%) had consumed NSAIDs predominantly in combinations with paracetamol, aspirin, phenacetin, caffeine, and/or traditional herbal medications. Of those patients who consumed NSAIDs alone, 17 had consumed only a single type of NSAID and the remaining 12 had consumed multiple types of NSAIDs. The amount of NSAIDs administered ranged from 1,000 to 26,600 capsules or tablets over a 2- to 25-year period. Renal impairment (serum creatinine, 126 to 778 mumol/L) was noted in 26 of these 38 patients (64.8%). The reasons given for consuming NSAIDs include gouty arthritis (18 patients), osteoarthritis (seven patients), rheumatoid arthritis (six patients), chronic headache (three patients), gouty arthritis plus chronic headache (three patients), and chronic backache (one patient). All patients were prescribed these drugs and were followed medically. The occurrence of analgesic nephropathy was predominantly in males (male to female ratio, 1.9:1). Most of the patients did not have the characteristic psychological profile attributed previously to analgesic abuse nephropathy. Associated addictive habits, such as the use of psychotropic drugs and sleeping tablets, purgative abuse, and alcoholism, were absent.(ABSTRACT TRUNCATED AT 250 WORDS)

Risk factors for kidney cancer in New South Wales, Australia. II. Urologic disease, hypertension, obesity, and hormonal factors

In a population-based case-control study of kidney cancer in New South Wales, Australia, data from structured interviews with 489 cases of renal cell cancer (RCC) and 147 cases of renal pelvic cancer (CaRP) diagnosed in 1989 and 1990, and 523 controls from the electoral rolls, confirmed the link between obesity and RCC. In addition, regular consumption of 'diet' pills independently increased the risk for this cancer. A diagnosis of hypertension at least two years before interview raised the risk for RCC, and regular use of beta-blockers, a class of antihypertensive drug, independently increased the risk for RCC and CaRP (risk ratio = 1.5-1.8). No independent effect was found for use of diuretics. Additional information provided by this study includes increased risks associated with kidney injury (RCC, CaRP)--possibly attributed to recall bias--and kidney infection (CaRP), as well as a nonsignificantly raised risk linked with kidney stones (RCC, CaRP) and a significantly reduced risk for RCC in persons giving a history of lower urinary tract infection. No significant association of RCC was found with hormonal factors (age at menarche or menopause; child-bearing; regular use of oral contraceptives or estrogens; hysterectomy or oophorectomy).

Epidemiologic study of analgesic abuse: mortality study in 7275 working women (1968-1987)

In a prospective, longitudinal investigation over a period of 20 years in 7275 working women 30 to 49 years old, we examined the effect of the ingestion of analgesics on cause-specific mortality. Evidence of intake of phenacetin and salicylate containing analgesics was obtained at a urine screening in 1967 and was shown to relate to intake between 1968 to 1978. Life table analysis of the effect of phenacetin intake on overall mortality showed significant differences between the groups of women with intake (N = 613) versus no intake (N = 4175): for total [relative risk (RR) = 2.1, P less than 0.001], urorenal (RR = 24.4, P less than 0.001), cardiovascular (RR = 4.5, P less than 0.001), and cancer mortality (RR = 1.9, P less than 0.001). No significant effects on overall or cause-specific mortality were found for salicylate intake. These results make a causal relationship between the amount of analgesic containing phenacetin consumed and the risk of death from urorenal disease likely. Furthermore, the data show an elevated risk for cardiovascular disease and cancer for phenacetin intake. No such relationships are demonstrable for the use of salicylate.

Decreased incidence of diphenylamine-induced renal papillary necrosis in Syrian hamsters given dimethylsulphoxide

The renal papillotoxicity of diphenylamine dissolved in dimethylsulphoxide (DMSO) was investigated in male Syrian hamsters, male Sprague-Dawley rats and female Mongolian gerbils. When diphenylamine in DMSO was administered orally to male Syrian hamsters (400, 600 or 800 mg/kg body weight/day for up to 9 days), the incidence of renal papillary necrosis was almost zero. Hamsters pretreated with DMSO (0.5 ml/100 g body weight/day) and 1 hr later given 400, 600 or 800 mg diphenylamine in peanut oil/kg body weight/day for 3 consecutive days had significantly reduced incidences of renal papillary necrosis (0/10, 0/10 and 1/10 in the low-, mid- and high-dose groups, respectively) when compared with hamsters given similar doses of diphenylamine but not pretreated with DMSO (5/10, 7/10 and 5/10 in the low-, mid- and high-dose groups, respectively). Focal, apex-limited renal papillary necrosis was observed in two Sprague-Dawley rats given 800 mg diphenylamine in DMSO/kg body weight/day orally for 9 days. Focal, intermediate renal papillary necrosis was observed in two additional rats administered 800 mg diphenylamine in DMSO/kg/day orally for 9 days. Renal papillary necrosis was not observed in any of the Mongolian gerbils. The results of these studies suggest that DMSO protects against diphenylamine-induced renal papillary necrosis in male Syrian hamsters.

Analgesic nephropathy in Fischer 344 rats: comparative effects of chronic treatment with either aspirin or paracetamol

This study has compared the relative nephrotoxicity of chronic treatment with aspirin or paracetamol in an animal model. Changes in renal structure and urinary concentrating ability were examined in female Fischer 344 rats after continuous treatment with either aspirin (120-230 mg/kg body wt/day), or paracetamol (140-210 mg/kg body wt/day), and were compared with age-matched untreated control rats. Renal morphological changes were examined after 40-83 weeks of analgesic treatment, using light and electron microscopy. Aspirin caused renal papillary necrosis and a decrease in urinary concentrating ability, whereas paracetamol alone did not cause significant renal damage. Aspirin produced damage to the interstitial cells and matrix, particularly in the mid-papillary region, followed by changes to the thin limbs of the loop of Henle and medullary capillary endothelium. These structural changes were similar to those described previously, when continuous treatment with combined aspirin and paracetamol was studied in the same animal model.

An epidemiologic study of abuse of analgesic drugs. Effects of phenacetin and salicylate on mortality and cardiovascular morbidity (1968 to 1987)

BACKGROUND

Phenacetin abuse is known to produce kidney disease; salicylate use is supposed to prevent cardiovascular disease. We conducted a prospective, longitudinal epidemiologic study to examine the effects of these drugs on cause-specific mortality and on cardiovascular morbidity.

METHODS

In 1968 we evaluated a study group of 623 healthy women 30 to 49 years old who had evidence of a regular intake of phenacetin, as measured by urinary excretion of its metabolites, and a matched control group of 621 women. Salicylate excretion was also measured. All subjects were examined over a period of 20 years.

RESULTS

Life-table analyses of mortality during the 20 years, with adjustment for the year of birth, cigarette smoking, and length of follow-up, revealed significant differences between the groups in overall mortality (study group vs. control group, 74 vs. 27 deaths; relative risk, 2.2; 95 percent confidence interval, 1.5 to 3.3), deaths due to urologic or renal disease (relative risk, 16.1; 95 percent confidence interval, 3.9 to 66.1), deaths due to cancer (relative risk, 1.9; 95 percent confidence interval, 1.1 to 3.3), and deaths due to cardiovascular disease (relative risk, 2.9; 95 percent confidence interval, 1.5 to 5.5). The relative risk of cardiovascular disease (fatal or nonfatal myocardial infarction, heart failure, or stroke) was 1.8, and the 95 percent confidence interval 1.3 to 2.6. The odds ratio for the incidence of hypertension was 1.6, and the 95 percent confidence interval 1.2 to 2.1. The effects of phenacetin on morbidity and mortality, with adjustment for base-line salicylate excretion, were similar. In contrast, salicylate use had no effect on either mortality or morbidity.

CONCLUSIONS

Regular use of analgesic drugs containing phenacetin is associated with an increased risk of hypertension and mortality and morbidity due to cardiovascular disease, as well as an increased risk of mortality due to cancer and urologic or renal disease. The use of salicylates carries no such risk.

Progression of renal insufficiency in analgesic nephropathy: impact of continuous drug abuse

Twenty-three patients with analgesic nephropathy and apparent cessation of drug abuse were tested for blood acetaminophen and salicylate on the occasion of routine renal control examinations. In 12 patients (mean creatinine level 2.74 +/- 1.09 mg/dl) no deterioration of renal function was noted within a 1-year observation period (Group 1). In 11 patients a significant progression of renal insufficiency was observed (mean creatinine level rose from 3.86 +/- 1.06 to 6.40 +/- 3.18 mg/dl within the same observation period; Group 2). Blood tests for acetaminophen and salicylate were positive in 2 patients of Group 1 and in 9 patients of Group 2 (chi 2 = 7.326), p less than 0.01). Our data emphasize the importance of a continuous analgesic abuse hidden from the medical staff with regard to the progression of renal insufficiency in analgesic nephropathy.

Geographical distribution of cancers of the kidney and urinary tract and analgesic nephropathy in Australia and New Zealand

Age-standardised incidence rates for cancers of the renal parenchyma, renal pelvis and bladder and for end-stage renal failure due to analgesic nephropathy for the years 1982-83 were compared between the Australian states and New Zealand, and within New South Wales (NSW), to determine whether these rates paralleled the previous prevalence of consumption of phenacetin-containing analgesics. Whereas little variation was seen within Australasia in respect of the incidence of cancer of the renal parenchyma and bladder, both cancer of the renal pelvis and end-stage renal failure due to analgesic nephropathy had higher incidence rates amongst women in NSW and Queensland than in the other states or New Zealand. Within NSW, the average annual incidence rates during 1973-82 for renal pelvic cancer in the Hunter region of 1.3 (m) and 1.6 (f) per 100,000 were the highest in the state. These high incidence rates coincided with areas known to have had a high prevalence of consumption of compound analgesics containing phenacetin. In an international comparison with populations which had published incidence rates for each of the periods 1973-77 and 1978-82, the rate for cancer of the renal pelvis in women was highest in both time periods in NSW and had increased absolutely at a faster rate.

Morbidity of patients with analgesic-associated nephropathy on regular dialysis treatment and after renal transplantation

In a retrospective study, patients with end-stage renal failure from analgesic-associated nephropathy - 55 on regular dialysis treatment and 12 after renal transplantation - were under observation for 57 and 33 months, respectively. Of these 34 patients on chronic hemodialysis had suffered from different cardiovascular diseases. Hypertriglyceridemia was diagnosed in 62% of the patients, arterial hypertension requiring antihypertensive therapy in 44%. In three patients (5%) carcinoma of the urinary bladder were diagnosed. The leading causes of death in 21 patients included cardiovascular diseases (29%), hyperkalemia (19%), sepsis, and malignant tumors (14% each). Rejection occurred in 3 out of 12 patients after renal transplantation. Again, cardiovascular morbidity was high (58%) with coronary heart disease being present in 33% of the patients. Hypertriglyceridemia was observed in 5 out of 6 patients, antihypertensive therapy was needed in 50%. One patient died from primary pulmonary hypertension.

The effect of acetaminophen on pig kidneys with a 2-bromoethanamine-induced papillary necrosis

Large White pigs were used to investigate the effects of acetaminophen (paracetamol) on normal kidneys or those with an existing renal papillary necrosis. Pairs of young female animals were treated with either a single iv dose of 50 mg/kg 2-bromoethanamine (BEA), 100 mg/kg/day acetaminophen po for 28 days, or a combination of BEA followed by the acetaminophen treatment. Two pigs served as untreated controls. Kidney length, diameter and parenchymal thickness were measured by ultrasound scans, and glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) assessed by 99mTc-DTPA and 131I-hippuran renography prior to treatment and on day 26. Acetaminophen only caused no renal pathology. Despite the lack of a gross RPN, hyperplasia of the pelvic and ureteric urothelia (with extensive vacuolation) was observed following BEA, but BEA followed by acetaminophen for 28 days did not enhance the lesion. The BEA and BEA-acetaminophen groups (but not acetaminophen only) showed an increased ERPF compared with age-matched controls, but there was no significant difference in the overall GFR between the groups.

Epidemiology and mechanistic basis of analgesic-associated nephropathy

End-stage renal failure (ESRF) due to analgesic nephropathy is still a common clinical condition in several countries, but the prevalence in dialysis patients shows large geographical differences. The frequency of ESRF of unknown aetiology is the inverse of that linked to analgesic abuse, and data suggest that the occurrence of analgesic nephropathy may be underestimated. The study of analgesic nephropathy is difficult because the earliest damage to the kidney is a renal papillary necrosis (RPN), which cannot easily be diagnosed. Continued analgesic abuse generally leads to a progressive secondary cortical degeneration which is easier to diagnose. If analgesic abuse is stopped at an early enough stage in nephropathy, clinical symptoms stabilize or improve, and ESRF may be averted. A high incidence of upper urothelial carcinoma (UUC) is also observed in individuals with a history of analgesic abuse, but it is still not clear if the two have a related pathogenesis. Study of the mechanism of RPN in animals administered analgesics and nonsteroidal antiinflammatory drugs (NSAID) has been difficult owing to their extrarenal toxicity. Several model compounds cause identical clinical changes and have as their selective target the renal medullary interstitial cells; subsequently, other changes (including cortical and glomerular degeneration) develop as a secondary cascade. A number of mechanisms have been proposed to explain RPN (e.g., counter-current concentrating mechanism, ischaemic injury, altered prostaglandin metabolism, immunological changes), but peroxidative metabolism of papillotoxic chemicals within the interstitial cells seems to be the most likely cause. Analgesic abuse is a costly socioeconomic condition for which there is currently no clinical treatment. If it is diagnosed early enough, severe renal degeneration can be prevented. Additional epidemiological information is needed to establish the causative role of analgesics and other chemicals, in order to determine the relative risk of each. Additional animal experiments are needed in order to clarify the molecular pathogenesis of RPN and UUC, to differentiate the stages in progression to ESRF and to develop more sensitive and selective diagnostic criteria.

The clinical utility of renal concentrating capacity in polycystic kidney disease

We studied 177 adult nonazotemic subjects with autosomal dominant polycystic kidney disease (ADPKD) and 123 unaffected family members (NADPKD). In order to assess the factors influencing renal concentrating capacity maximal urinary osmolality (UOsm) after overnight water deprivation and vasopressin was measured. UOsm was reduced in ADPKD (680 +/- 14) compared to NADPKD subjects (812 +/- 13 mOsm/kg). A greater severity of the architectural abnormality as assessed by cyst number and size and remaining volume of normal parenchyma was associated with a greater impairment of renal concentrating capacity. The concentrating defect was present in the youngest ADPKD subjects and the rate of decline of concentrating capacity with age in ADPKD paralleled that in NADPKD subjects. Based on the initial 135 subjects studied, we developed an algorithm for diagnostic screening for ADPKD utilizing blood pressure, serum creatinine and UOsm designed to maximize sensitivity. When applied to a subsequent population of 165 adults, 121 with ADPKD and 44 unaffected relatives, this algorithm would have spared 20% of unaffected subjects from the cost of ultrasound while failing to detect less than 2% of affected subjects. This simple protocol thus offers a rapid and inexpensive way to screen for ADPKD.

Nonsteroidal antiinflammatory drug-induced renal dysfunction related to inhibition of renal prostaglandins

This article reviews the role of prostaglandins (PG) in maintaining renal function in the face of vasoconstrictive substances and decreased renal blood flow. Inhibition of the synthesis of renal PG by nonsteroidal antiinflammatory drugs (NSAID) may lead to the development of hemodynamically induced renal dysfunction in patients with a decreased effective plasma volume or chronic renal insufficiency. The importance of stimulation of renal PG activity to the action of diuretics and a pharmacodynamic mechanism for NSAID-induced diuretic resistance are presented. Evidence for the relative selectivity of sulindac in inhibiting systemic PG without inhibiting renal PG is also reviewed. Inhibition of renal PG synthesis has been postulated to be a contributing factor for other forms of NSAID-induced renal dysfunction (interstitial nephritis, analgesic-associated nephropathy). The relationship between renal PG inhibition by NSAID and these syndromes is briefly discussed. Considering the frequent use of NSAID, it is important that practitioners are aware of the mechanisms whereby patients may develop NSAID-induced renal dysfunction and that they are able to identify patients at risk.

Aspirin, paracetamol and non-steroidal anti-inflammatory drugs. A comparative review of side effects

Non-steroidal anti-inflammatory drugs (NSAIDs) effectively control the symptoms of many of the rheumatic diseases although they have little effect on the underlying causes. Their effect is mainly on the mediators of the inflammatory process. Unfortunately, these mediators have important physiological roles in the maintenance of health, particularly in the gastrointestinal tract and the kidney, so that their inhibition results in many unwanted reactions of varying severity. The mechanisms underlying these reactions are described. Their occurrence varies, both qualitatively and quantitatively, and an attempt is made to assess these differences, although it may be that they are related directly to differences in dosage and therapeutic efficacy. In addition, immunologically mediated adverse reactions occur. These mechanisms are outlined and related to the clinical picture. There are considerable differences in frequency of reactions between the compounds: in particular there is a wide variation in the rate of dermatological reactions of this type. Agranulocytosis has been particularly associated with the pyrazolone compounds, although it has been reported with most others. Aplastic anaemia, which may not be an immune-mediated reaction, is also thought of as a pyrazolone reaction, but the incidence with indomethacin approaches a similar level. Although all drugs analysed may cause hepatic reactions, these are rare except with the now withdrawn benoxaprofen. Several types of immunologically mediated renal reactions occur and these rarities are also described. Paracetamol does not have any effect on the inflammatory mediators. Anxieties about this substance relates to the parent compound phenacetin and its necrotic effect on the renal papillae. There is extensive literature on this subject concerning not only paracetamol, but also aspirin and other NSAIDs. This is also assessed and summarised. The danger of paracetamol as a direct hepatic toxin in self-poisoning is discussed. Novel NSAIDs are introduced and others withdrawn with frequent and monotonous regularity. Sometimes the reasons have some medical or scientific plausibility, but often they are over-reactions by registration authorities or pharmaceutical companies in response to uninformed media publicity. The problems of the numerically and scientifically accurate collection and assessment of adverse reaction data are legion and as a result useful agents have been lost. Some of these difficulties are described, and some non-drug 'adverse reactions' are described.(ABSTRACT TRUNCATED AT 400 WORDS)

Transitional cell tumors of the renal pelvis and ureter associated with capillarosclerosis indicating analgesic abuse

An association between transitional cell tumors (TCT) and abuse of compound analgesics has been established during the past two decades. Recently thickening of basement membranes around subepithelial capillaries, known as capillarosclerosis, has been reported as a change in the urinary tract pathognomonic for a long-standing abuse of compound analgesics. Therefore the authors reviewed pathologic and clinical data in 59 patients treated for TCT of the renal pelvis or ureter. Capillarosclerosis was found in nine cases (15%) of the TCT group but not in any of the cases selected as controls. Capillarosclerosis is suggested as a valuable marker, which always should be looked for in bladder biopsy specimens. Whenever present it should arouse suspicion of analgesic abuse, and the associated increased risk for developing TCT of the renal pelvis or ureter should be borne in mind.

Analgesic-associated nephropathy

Although the question of whether or not analgesic abuse leads to a certain type of nephropathy has been investigated since 1953, no conclusive answer has been forthcoming. Epidemiologic investigations on the correlation between analgesic abuse and renal function as well as experimental animal studies have given contradictory results concerning the possibility of analgesic-associated kidney damage. However, studies on the correlation between analgesic abuse and papillary necrosis have demonstrated that this lesion coincides in 69% of the cases with an analgesic history. Follow-up studies of patients with analgesic nephropathy have shown that renal function deteriorates in 60% of the patients with continued abuse and that it stabilizes in 80% of the patients after cessation of abuse. Studies on the legislative restriction of phenacetin/acetaminophen, carried out mostly in Scandinavian countries since 1965, show a 50%-90% decline in signs of analgesic nephropathy (papillary necrosis) following a reduction in the sale of these drugs. The prevalence of analgesic abuse may be underestimated, since up to 80% of the abusers tend to deny their analgesic intake. Obviously, only a small percentage of analgesic abusers (approximately 1%) finally develop nephropathy. Even though the results of epidemiologic and experimental studies are contradictory, the results of investigations on papillary necrosis and on legislative prevention as well as of patient follow-ups tend to indicate a correlation between analgesic abuse and a well-defined type of nephropathy.

Renal toxicity of non-steroidal anti-inflammatory drugs

Non-steroidal anti-inflammatory drugs represent the most heavily prescribed and used class of drugs in human medicine. Most are derivatives of either salicylates, propionic acid, indoleacetic acid, anthranilic acid, pyrazolone, or oxicams. They depress the synthesis of prostaglandins from arachidonic acid by reversible inhibition of the enzyme cyclooxygenase. In the kidney, prostaglandins PGE2 and PGI2 modulate the vasoconstrictor effects of angiotensin II, norepinephrine, and vasopressin. In the presence of volume contraction, anesthesia, or disease states associated with high levels of these hormones, prostaglandins regulate glomerular filtration, vascular resistance, and renin secretion. They additionally influence urine volume and sodium content. In man, a syndrome of analgesic abuse that has been identified worldwide occurs more frequently in females than males and can result in severe renal damage, most notably renal papillary necrosis. Most common laboratory animals are relatively resistant to developing the renal lesion associated with NSAIDs unless high doses are given over long periods of time and some withholding of water is introduced into the protocol. Diuresis with 5% dextrose and water is protective. Studies of paracetamol and salicylate have demonstrated that these compounds concentrate in the papillary tip of the kidney at concentrations of 4 to 13 times the plasma levels in dogs and rabbits, respectively. Renal papillary necrosis has been described in horses on maintenance doses of phenylbutazone where dehydration or reduced water consumption has occurred. The lesion can be reproduced experimentally if water is withheld during a portion of the dosing interval. An increased incidence of uroepithelial tumors have been reported in patients with a history of analgesic abuse.(ABSTRACT TRUNCATED AT 250 WORDS)

Formation of reactive metabolites of phenacetin in humans and rats

The metabolism of phenacetin to reactive intermediates in humans was estimated from the excretion of thio adducts in urine. N-Hydroxyphenacetin, a precursor of reactive metabolites, was also quantified. Following an oral dose of phenacetin (10 mg/kg) to humans, these metabolites in 24 h urine were: paracetamol-3-cysteine, 4.4% dose; paracetamol-3-mercapturate, 3.9%; 3-thiomethylparacetamol, 0.4%; N-hydroxyphenacetin, 0.5%. Rats showed a considerable increase in N-hydroxyphenacetin excretion after chronic dosing with phenacetin at high dosage (500 mg/kg) for one month. chronic dosing with a low dose (50 mg/kg) did not increase N-hydroxyphenacetin excretion, but a marked increase occurred on concomitant administration of aspirin and caffeine.

Effects of nonsteroidal anti-inflammatory drugs on prostaglandins and renal function

In the past 15 years, there has been an explosion in the number of nonsteroidal anti-inflammatory drugs on the market. Along with this explosion have come increasing reports of the physiologic and pathologic changes seen in the kidneys. This report reviews the effects of prostaglandins on the kidney and the physiologic changes that result when prostaglandin synthesis is blocked. The world literature on renal complications of nonsteroidal anti-inflammatory drugs is reviewed and 274 cases of acute renal disease associated with their use are reported. The following cases are described: nephrotic syndrome (34); acute interstitial nephritis (51); acute tubular necrosis (29); papillary necrosis (53); poor perfusion with renal failure (40); acute glomerulitis or vasculitis (13); and unspecified renal failure (102). Fenoprofen appeared to be more nephrotoxic than other nonsteroidal anti-inflammatory drugs and resulted in multiple renal lesions in the same patient.