Analgesic use and chronic renal failure: a critical review of the epidemiologic literature

Acute kidney injury associated with non-steroidal anti-inflammatory drugs

Non-steroidal anti-inflammatory drugs (NSAIDs) are ones of the commonly prescribed drugs worldwide. They primarily inhibit cyclooxygenase (COX) enzyme which is responsible for conversion of phospholipids to various prostaglandins (PGs). Disruption in PGs production affects the kidneys in several ways, including vasoconstriction that may result in ischemic acute kidney injury (AKI) in at-risk patients. They also impair salt and water excretion, leading to edema and hypertension. Other complications include hyperkalemia, hyponatremia, nephrotic syndrome, acute interstitial nephritis and chronic kidney disease progression. AKI from NSAIDs is usually reversible with favorable prognosis after discontinuation of NSAIDs. Avoidance of NSAIDs exposure is extremely important, especially among high-risk patients.

Prescription, over-the-counter (OTC), herbal, and other treatments and preventive uses for COVID-19

The current COVID-19 pandemic has spread rapidly worldwide and has challenged fragile health care systems, vulnerable socioeconomic conditions, and population risk factors, and has led to an overwhelming tendency to misuse prescription drugs and self-medication with prescription drugs, over-the-counter (OTC) drugs, herbals products, and unproven chemicals as a desperate preventive or curative measure for COVID-19. In this chapter, we present the legislative differences between prescription drugs, OTC drugs, and herbals. Various approved and nonapproved prescription and OTC drugs as symptomatic treatment for COVID-19 are listed and evaluated based on their reported efficacy, safety, and toxicological profile. We also present the various herbal products that are currently studied and used as treatment and preventive for COVID-19. The efficacy, toxicology profile, safety, and legal issues of some speculative preventive and treatment options against COVID-19, such as Miracle Mineral Solution (MMS), chlorine dioxide solution (CDS), colloidal silver, and hydrogen peroxide is presented. The chapter also emphasizes the specific strategies that need to be implemented to guide the population in the effective and safe use of prescribed medications, such as the Medication Therapy Management or Pharmaceutical Care process. Finally, this chapter aims to provide a deeper insight into the lack of health literacy in the population and the effect that drug utilization research (DUR) has in the decision making of health authorities and general public. We aim to provide the current information about the various treatment and preventive options used for COVID-19.

Self-medication practices during the COVID-19 pandemic among the adult population in Peru: A cross-sectional survey

Self-medication impacts both negatively and positively the health of people, which has become evident during the COVID-19 pandemic. The study aimed to assess the prevalence of self-medicated drugs used for respiratory symptoms, as COVID-19 preventive, for its symptoms or once tested positive. To determine the perception of symptom relief and demographic variables that promote self-medication in Peru. We performed a cross-sectional, analytical, multicenter study in 3792 study respondents on the use, the reason for use, and perception of relief after the use of six drugs during the quarantine period. An online questionnaire was developed, pretested and submitted to the general public. Multivariable logistic regression was used to ascertain factors that influence an individual's desire to self-medicate, associations were considered significant at p < 0.05 and using region (coast, mountain and jungle) as cluster group. The majority of respondents self-medicated with acetaminophen for respiratory symptoms and mainly because they had a cold or flu. It was observed that all the surveyed drugs (acetaminophen, ibuprofen, azithromycin, penicillin, antiretrovirals and hydroxychloroquine) were consumed for various symptoms including: fever, fatigue, cough, sneezing, muscle pain, nasal congestion, sore throat, headache and breathing difficulty. Over 90% of respondents perceived relief of at least one symptom. Multivariable logistic regression showed that older people have a higher frequency of antiretroviral self-medication, respondents who currently have a job had a higher frequency of penicillin self-medication, and that respondents from the Andes consumed less acetaminophen, while the ones from the rainforest consumed it more. There were significant percentages of self-medication, including drugs without sufficient scientific evidence. Age, region where one lived and job status were variables associated with self-medication frequency. Continuous awareness and sensitization about the risks of self-medication are warranted.

Acute Pain Management Pharmacology for the Patient with Concurrent Renal or Hepatic Disease

The clinical utility of most analgesic drugs is altered in the presence of patients with impaired renal or hepatic function not simply because of altered clearance of the parent drug, but also through production and accumulation of toxic or therapeutically active metabolites. Some analgesic agents may also aggravate pre-existing renal and hepatic disease.

A search was performed, taking in published articles and pharmaceutical data to determine available evidence for managing acute pain effectively and safely in these two patient groups. The resulting information consisted mainly of small group pharmacokinetic studies or case reports, which included a large variation in degree of organ dysfunction.

In the presence of renal impairment, those drugs which exhibit the safest pharmacological profile are alfentanil, buprenorphine, fentanyl, ketamine, paracetamol (except with compound analgesics), remifentanil and sufentanil: none of these deliver a high active metabolite load, or suffer from significantly prolonged clearance. Amitriptyline, bupivacaine, clonidine, gabapentin, hydromorphone, levobupivacaine, lignocaine, methadone, mexiletine, morphine, oxycodone and tramadol have been used in the presence of renal failure, but do require specific precautions, usually dose reduction. Aspirin, dextropropoxyphene, non-steroidal anti-inflammatory drugs and pethidine, should not be used in the presence of chronic renal failure due to the risk of significant toxicity.

In the presence of hepatic impairment, most drugs are subject to significantly impaired clearance and increased oral bioavailability, but are poorly studied in the clinical setting. The agent least subject to alteration in this context is remifentanil; however the drugs’ potency has other inherent dangers. Other agents must only be used with caution and close patient monitoring. Amitriptyline, carbamazepine and valproate should be avoided as the risk of fulminant hepatic failure is higher in this population, and methadone is contraindicated in the presence of severe liver disease.

Analgesic Nephropathy–-A Painful Progression

One of the dreaded complications of long term analgesic intake is nephrotoxicity characterized by chronic interstitial nephritis and papillary necrosis. Much of the literature of its epidemiology dates back to 1960s and its impact on present day society is not well documented. Non steroidal anti inflammatory agents reduce pain by blocking prostaglandin generation. Prostaglandins have renal vaso dilatory effects in states of volume depletion to counteract the vasoconstrictive pressor hormones. Earlier analgesic tablets contained a mixture of aspirin, phenacetin and caffeine. Phenacetin and its metabolites have nephrotoxic potential and incidence of analgesic nephropathy was brought down in countries where it was banned. The concentration of phenacetin and its metabolite acetaminophen is increased at the tip of renal papilla due to counter current concentrating mechanism of the loop of henle. These are potent oxidants leading to cell injury due to lipid peroxidation, though their effects are normally counterbalanced by anti oxidant glutathione. Glutathione deficiency at the medulla can be precipitated by co ingestion of aspirin. The exact dose of analgesics which needs to be ingested is unclear but a daily ingestion of 5–8 tablets over 5 years results in clinical nephrotoxicity. The histopathology is one of chronic interstitial nephritis with renal fibrosis. Clinically the patient presents with polyuria, asthenia and anemia. The diagnosis is suspected in a patient with progressive chronic kidney disease without proteinuria. CT imaging of the kidneys show irregular scarred kidneys with papillary calcification and necrosis. Recently, COX-2 inhibitors are promoted as renal safe drugs, but may not be so given the multiple case reports of renal toxicity in post marketing surveys. The treatment of analgesic nephropathy includes discontinuation of offending drug, protein restricted diet, control of blood pressure and statins. In conclusion analgesic nephropathy is a preventable cause of chronic kidney disease and both the patients and treating physicians should be mindful of the potential nephrotoxcity of nonsteroidal anti inflammatory agents when administered for prolonged periods without monitoring renal function.

Notoginsenoside R1 ameliorates podocyte injury in rats with diabetic nephropathy by activating the PI3K/Akt signaling pathway

The present study was designed to examine the protective effect of notoginsenoside R1 (NR1) on podocytes in a rat model of streptozotocin (STZ)-induced diabetic nephropathy (DN), and to explore the mechanism responsible for NR1-induced renal protection. Diabetes was induced by a single injection of STZ, and NR1 was administered daily at a dose of 5 mg/kg (low dose), 10 mg/kg (medium) and 20 mg/kg (high) for 16 weeks in Sprague-Dawley rats. Blood glucose levels, body weight and proteinuria were measured every 4 weeks, starting on the day that the rats received NR1. Furthermore, on the day of sacrifice, blood, urine and kidneys were collected in order to assess renal function according to general parameters. Pathological staining was performed to evaluate the renal protective effect of NR1, and the expression of the key slit diaphragm proteins, namely neprhin, podocin and desmin, were evaluated. In addition, the serum levels of inflammatory cytokines [tumor necrosis factor-α (TNF-α), tumor growth factor-β1 (TGF-β1), interleukin (IL)-1 and IL-6] as well as an anti-inflammatory cytokine (IL-10) were assessed, and the apoptosis of podocytes was quantified. Finally, the phosphoinositide 3-kinase (PI3K)/Akt signaling pathway and the involvement of nuclear factor-κB (NF-κB) inactivation was further analyzed. In this study, NR1 improved renal function by ameliorating histological alterations, increasing the expression of nephrin and podocin, decreasing the expression of desmin, and inhibiting both the inflammatory response as well as the apoptosis of podocytes. Furthermore, NR1 treatment increased the phosphorylation of both PI3K (p85) and Akt, indicating that activation of the PI3K/Akt signaling pathway was involved. Moreover, NR1 treatment decreased the phosphorylation of NF-κB (p65), suggesting the downregulation of NF-κB. This is the first study to the best of our knowledge, to clearly demonstrate that NR1 treatment ameliorates podocyte injury by inhibiting both inflammation and apoptosis through the PI3K/Akt signaling pathway.

Status of non-steroidal anti-inflammatory drugs use and its association with chronic kidney disease: a cross-sectional survey in China

AIM

Non-steroidal anti-inflammatory drugs (NSAIDs) have been reported to be associated with adverse effects including kidney injury, while relevant studies from developing countries are limited. We aimed to explore the status of NSAIDs use in China, as well as cross-sectional association between NSAIDs intake and presence of chronic kidney disease (CKD).

METHODS

A national representative sample of 47,204 adults in China was used. Prevalence of regular NSAIDs use was reported. Age- and sex- matched controls of NSAIDs users were then selected. The association between NSAIDs use and kidney injury were analyzed using logistic regression.

RESULTS

Altogether 1129 participants reported regular use of NSAIDs, with the adjusted prevalence of 3.6% (95% CI, 3.2%-3.9%). And 76.9% of them (n = 868) had taken phenacetin-containing analgesics, with an adjusted prevalence of 3.2% (95% CI, 2.9%-3.5%). After adjusting for potential confounders, long-term NSAIDs intake (≥ 48 months) was associated with eGFR < 60 mL/min per 1.73 m2, with an OR of 2.36 (95% CI, 1.28-4.37).

CONCLUSION

Regular use of NSAIDs, especially phenacetin-containing drugs, is prevalent in China. And long-term NSAIDs intake (≥ 48 months) was independently associated with reduced renal function.

Association of individual non-steroidal anti-inflammatory drugs and chronic kidney disease: a population-based case control study

Background

Non-steroidal anti-inflammatory agents (NSAIDs) are known to be associated with renal damage. No clear evidence exists regarding differential risk of chronic kidney disease (CKD), specifically, across various NSAIDs.

Aim

The aim of this population-based case-control study was to evaluate the association between use of individual NSAIDs and risk of CKD in a general population of Southern Italy.

Methods

A nested case-control study was carried out using the general practice Arianna database, identifying incident CKD patients as cases and matched controls from 2006 to 2011. The date of first CKD diagnosis was defined as the index date (ID). Conditional logistic regressions were performed to estimate the risk of CKD associated with NSAIDs by class and individual drugs as compared to non-use during different time windows (within one year, six or three months prior to ID), with the latter being defined as current users. Among current users, the effect of cumulative exposure to these drugs was evaluated.

Results

Overall, 1,989 CKD cases and 7,906 matched controls were identified. A statistically significant increase in the risk of CKD was found for current users of oxicams (adjusted OR: 1.68; 95% CI: 1.15-2.44) and concerning individual compounds, for ketorolac (adj. OR: 2.54; 95% CI: 1.45-4.44), meloxicam (adj. OR: 1.98; 95% CI: 1.01-3.87) and piroxicam (adj. OR: 1.95; 95% CI: 1.19-3.21).

Conclusions

The risk of CKD varies across individual NSAIDs. Increased risk has been found for ketorolac, which may precipitate subclinical CKD through acute renal damage, and long-term exposure to oxicams, especially meloxicam and piroxicam.

The ban on phenacetin is associated with changes in the incidence trends of upper-urinary tract cancers in Australia

BACKGROUND

Phenacetin is an analgesic that causes renal diseases and cancers of the upper-urinary tract (UUT). It was banned in most countries from the late 1960s. This study aimed to evaluate, for the first time, the long-term population impact of the phenacetin ban on UUT cancer rates.

METHODS

We used cancer registry data from Australia, where phenacetin was widely used, to study age- and sex-specific incidence trends of cancers of the renal pelvis and the ureter after the phenacetin ban (1979). Incidence rate ratios and average annual percentage change (AAPC) were calculated to quantify changes in rates over time.

RESULTS

Incidence rates of renal pelvis cancer decreased by 52% in women and 39% in men between 1983-1987 and 2003-2007. The decline in women was stronger in states where the use of phenacetin was the most widespread, e.g. New South Wales (AAPC: -4.1%; 95% CI -5.3, -2.9) and Queensland (AAPC: -3.3%; 95% CI -4.9, -1.8), and after the mid-1990s. Incidence rates of ureteral cancer remained stable for both sexes throughout the study period.

CONCLUSIONS

Our findings strongly suggest a beneficial impact of the ban on phenacetin on the incidence of renal pelvis cancer in Australia, particularly among women.

Non-steroidal anti-inflammatory drugs and chronic kidney disease progression: a systematic review

BACKGROUND

Non-steroidal anti-inflammatory drugs (NSAIDs) are widely regarded as one risk factor, which influences chronic kidney disease (CKD) progression. However, previous literature reviews have not quantified the risk in moderate to severe CKD patients.

OBJECTIVE

To estimate the strength of association between chronic NSAID use and CKD progression.

METHODS

We conducted a systematic review and meta-analysis of observational general practice or population studies featuring patients aged 45 years and over. The electronic databases searched were MEDLINE, EMBASE, Cochrane, AMED, BNI and CINAHL until September 2011 without date or language restrictions. Searches included the reference lists of relevant identified studies, WEB of KNOWLEDGE, openSIGLE, specific journals, the British Library and expert networks. For relevant studies, random effects meta-analysis was used to estimate the association between NSAID use and accelerated CKD progression (estimated glomerular filtration rate decline ≥ 15 ml/min/1.73 m2).

RESULTS

From a possible 768 articles, after screening and selection, seven studies were identified (5 cohort, 1 case-control and 1 cross-sectional) and three were included in the meta-analysis. Regular-dose NSAID use did not significantly affect the risk of accelerated CKD progression; pooled odds ratio (OR) = 0.96 (95%CI: 0.86-1.07), but high-dose NSAID use significantly increased the risk of accelerated CKD progression; pooled OR = 1.26 (95%CI: 1.06-1.50).

CONCLUSIONS

The avoidance of NSAIDs in the medium term is unnecessary in patients with moderate to severe CKD, if not otherwise contraindicated. As the definition of high-dose of NSAID use remains unclear, the lowest effective dose of NSAIDs should be prescribed where indicated.

Pattern of self-medication with analgesics among Iranian University students in central Iran

Background:

Self-medication is defined as the use of drugs for the treatment of self-diagnosed disorders. It is influenced by factors such as education, family, society, law, availability of drugs and exposure to advertisements. This study was performed to evaluate self-medication with analgesics and its pattern among different groups of Iranian University Students.

Materials and Methods:

A randomized, cross-sectional, multicenter study was conducted from December 2009 to February 2010. The target population of this study was 564 students out of 10,000 students attending four medical and non-medical science universities in Qom state. Data was analyzed using SPSS version 16, and analysis was conducted with descriptive analysis procedures.

Results:

76.6% of the students had used analgesics in self-medication in the previous 3 months. The frequency of analgesic use in the study period was once in 19.2% of the participants, twice in 22.2%, three times in 16.3% and more than three times in 35.5% of the participants, although 6.8% of them were not sure when they were used. Of all the respondents, 49.8% reported headache as the problem. This was the most common problem, after which came Dysmenorrhea,headache and stomach ache. Bone and joint pains were other problems that led to the use of analgesics. The most commonly used source of information for self-medication with analgesics was advice from friends and family (54.7%), previously prescribed medications (30.1%), their medical knowledge (13.3%) and recommendation of a pharmacist (1.9%).

Conclusion:

Self-medication with analgesics is very high among Iranian students in Qom city. This could be an index for other parts of the Iranian community. Because the source of information about analgesics is inappropriate, we would recommend education courses about analgesics and self-medication on the radio and television for the entire population.

Regular use of nephrotoxic medications is an independent risk factor for chronic kidney disease--results from a Chinese population study

BACKGROUND

Prescription drug abuse is an important global health concern. Our previous survey in Beijing indicates that nephrotoxic medication use is independently associated with chronic kidney disease (CKD).

METHODS

In the present study, the study population consisted of participants from our previous survey with a confirmed history of nephrotoxic medication use. Nephrotoxic mediations included three antipyretic analgesics (58.2%) and three Chinese traditional medicines containing aristolochic acids (CTM-AAs, 47.3%). Prevalence of CKD (defined by presence of albuminuria and/or reduced estimated glomerular filtration rate) as well as markers of tubular injury was analysed, and compared with 109 age- and sex-matched controls.

RESULTS

The prevalence of CKD was higher among medication users compared with controls, which was 18.3% and 8.5%, respectively. Among participants with medication use without CKD, markers of tubular injury including N-acetyl-β-d-glucosaminidase, transferrin and α(1)-microglobulin, were present in 26.6%. CKD was associated with CTM-AA use (cumulative AA-I dose > 0.5 g, OR = 5.625, P < 0.05) and antipyretic analgesic use (cumulative dose > 2.0 kg, OR = 3.848, P = 0.063) in a dose-dependent manner. Albuminuria and tubular injury persisted among CTM-AA users, but not among analgesic users after cessation of drug.

CONCLUSIONS

Our study suggests that education about rational analgesic use and CTM-AA banning may constitute an effective CKD prevention strategy.

Combined analgesics in (headache) pain therapy: shotgun approach or precise multi-target therapeutics?

BACKGROUND

Pain in general and headache in particular are characterized by a change in activity in brain areas involved in pain processing. The therapeutic challenge is to identify drugs with molecular targets that restore the healthy state, resulting in meaningful pain relief or even freedom from pain. Different aspects of pain perception, i.e. sensory and affective components, also explain why there is not just one single target structure for therapeutic approaches to pain. A network of brain areas ("pain matrix") are involved in pain perception and pain control. This diversification of the pain system explains why a wide range of molecularly different substances can be used in the treatment of different pain states and why in recent years more and more studies have described a superior efficacy of a precise multi-target combination therapy compared to therapy with monotherapeutics.

DISCUSSION

In this article, we discuss the available literature on the effects of several fixed-dose combinations in the treatment of headaches and discuss the evidence in support of the role of combination therapy in the pharmacotherapy of pain, particularly of headaches. The scientific rationale behind multi-target combinations is the therapeutic benefit that could not be achieved by the individual constituents and that the single substances of the combinations act together additively or even multiplicatively and cooperate to achieve a completeness of the desired therapeutic effect.As an example the fixed-dose combination of acetylsalicylic acid (ASA), paracetamol (acetaminophen) and caffeine is reviewed in detail. The major advantage of using such a fixed combination is that the active ingredients act on different but distinct molecular targets and thus are able to act on more signalling cascades involved in pain than most single analgesics without adding more side effects to the therapy.

SUMMARY

Multitarget therapeutics like combined analgesics broaden the array of therapeutic options, enable the completeness of the therapeutic effect, and allow doctors (and, in self-medication with OTC medications, the patients themselves) to customize treatment to the patient's specific needs. There is substantial clinical evidence that such a multi-component therapy is more effective than mono-component therapies.

Analgesics use and ESRD in younger age: a case-control study

BACKGROUND

An ad hoc peer-review committee was jointly appointed by Drug Authorities and Industry in Germany, Austria and Switzerland in 1999/2000 to review the evidence for a causal relation between phenacetin-free analgesics and nephropathy. The committee found the evidence as inconclusive and requested a new case-control study of adequate design.

METHODS

We performed a population-based case-control study with incident cases of end-stage renal disease (ESRD) under the age of 50 years and four age and sex-matched neighborhood controls in 170 dialysis centers (153 in Germany, and 17 in Austria) from January 1, 2001 to December 31, 2004. Data on lifetime medical history, risk factors, treatment, job exposure and intake of analgesics were obtained in a standardized face-to-face interview using memory aids to enhance accuracy. Study design, study performance, analysis plan, and study report were approved by an independent international advisory committee and by the Drug Authorities involved. Unconditional logistic regression analyses were performed.

RESULTS

The analysis included 907 cases and 3,622 controls who had never used phenacetin-containing analgesics in their lifetime. The use of high cumulative lifetime dose (3rd tertile) of analgesics in the period up to five years before dialysis was not associated with later ESRD. Adjusted odds ratios with 95% confidence intervals were 0.8 (0.7 - 1.0) and 1.0 (0.8 - 1.3) for ever- compared with no or low use and high use compared with low use, respectively. The same results were found for all analgesics and for mono-, and combination preparations with and without caffeine. No increased risk was shown in analyses stratifying for dose and duration. Dose-response analyses showed that analgesic use was not associated with an increased risk for ESRD up to 3.5 kg cumulative lifetime dose (98 % of the cases with ESRD). While the large subgroup of users with a lifetime dose up to 0.5 kg (278 cases and 1365 controls) showed a significantly decreased risk, a tiny subgroup of extreme users with over 3.5 kg lifetime use (19 cases and 11 controls) showed a significant risk increase. The detailed evaluation of 22 cases and 19 controls with over 2.5 kg lifetime use recommended by the regulatory advisors showed an impressive excess of other conditions than analgesics triggering the evolution of ESRD in cases compared with controls.

CONCLUSION

We found no clinically meaningful evidence for an increased risk of ESRD associated with use of phenacetin-free analgesics in single or combined formulation. The apparent risk increase shown in a small subgroup with extreme lifetime dose of analgesics is most likely an indirect, non-causal association. This hypothesis, however, cannot be confirmed or refuted within our case-control study. Overall, our results lend support to the mounting evidence that phenacetin-free analgesics do not induce ESRD and that the notion of "analgesic nephropathy" needs to be re-evaluated.

Identification of phenacetin metabolites in human urine after administration of phenacetin-C2H3: measurement of futile metabolic deacetylation via HPLC/MS-SPE-NMR and HPLC-ToF MS

The metabolism of acetyl-labelled phenacetin-C2H3 was investigated in man following a single (150 mg) oral dose. Urine samples were collected at predose, 0-2 h and >2-4 h post-dose, and samples from each time-point were then analysed directly using 1H-nuclear magnetic resonance (NMR) spectroscopy. The phenacetin metabolites acetaminophen (paracetamol) glucuronide, sulphate and the N-acetyl-L-cysteinyl conjugate were identified by this method, and all showed clear evidence of the loss of the original 2H3-acetyl label and its replacement with 1H3 (futile deacetylation). The observed percentage futile deacetylation by 1H-NMR spectroscopy was measured as approximately 20% in each metabolite (about 2% of the recovered dose). After sample preparation by solid-phase extraction on a C18 solid-phase extraction (SPE) cartridge, further profiling was performed using high-performance liquid chromatography/mass spectrometry-solid-phase extraction-nuclear magnetic resonance (HPLC/MS-SPE-NMR) confirming futile deacetylation had taken place as indicated by NMR spectroscopy on both the isolated acetaminophen glucuronide and L-cysteinyl-metabolites. Additional analysis by high-performance liquid chromatography-time-of-flight mass spectrometry (HPLC-ToF MS) identified further phenacetin metabolites, and from these data the mean percentage of futile deacetylation was measured as 31% +/- 2% for the acetylated phenacetin metabolites. A number of non-acetylated metabolites were also detected in the sample via HPLC-ToF MS. The results showed that phenacetin underwent a transient formation via a number of toxic intermediates to a much greater extent than had been observed in similar studies on acetaminophen. These results may contribute to the understanding of the analgesic nephropathy reported following chronic phenacetin consumption.

Tubulointerstitial nephritis associated with IgG4-related autoimmune disease

Autoimmune pancreatitis is a chronic fibroinflammatory condition primarily affecting the pancreas. Recent accumulating evidence suggested that autoimmune pancreatitis is a systemic autoimmune disease (immunoglobulin G4 [IgG4]-related autoimmune disease) affecting various organs with dense infiltration of IgG4-positive mononuclear cells. Tubulointerstitial nephritis is still a mysterious disease with an unknown cause. We report 2 cases of tubulointerstitial nephritis associated with autoimmune pancreatitis. In these patients, dense infiltrations of IgG4-positive mononuclear cells were observed in renal interstitium, with high serum IgG4 levels. Furthermore, in patient 1, who had sclerosing cholangitis, serum alkaline phosphatase and serum creatinine levels changed synchronously. Steroid therapy was followed by improved renal function and serum IgG4 levels in both patients. Because tubulointerstitial nephritis associated with IgG4-related autoimmune disease shows a favorable response to steroids and the renal dysfunction and pancreatic dysfunction are reversible, awareness of this entity is necessary for early diagnosis and prompt treatment. In addition, these cases support the hypothesis that IgG4-related autoimmune disease could be one cause of tubulointerstitial nephritis.

Detection of urinary drug metabolite (xenometabolome) signatures in molecular epidemiology studies via statistical total correlation (NMR) spectroscopy

Western populations use prescription and nonprescription drugs extensively, but large-scale population usage is rarely assessed objectively in epidemiological studies. Here we apply statistical methods to characterize structural pathway connectivities of metabolites of commonly used drugs detected routinely in 1H NMR spectra of urine in a human population study. 1H NMR spectra were measured for two groups of urine samples obtained from U.S. participants in a known population study. The novel application of a statistical total correlation spectroscopy (STOCSY) approach enabled rapid identification of the major and certain minor drug metabolites in common use in the population, in particular, from acetaminophen and ibuprofen metabolites. This work shows that statistical connectivities between drug metabolites can be established in routine "high-throughput" NMR screening of human samples from participants who have randomly self-administered drugs. This approach should be of value in considering interpopulation patterns of drug metabolism in epidemiological and pharmacogenetic studies.

Predicting initiation and progression of chronic kidney disease: Developing renal risk scores

Epidemiological studies have raised awareness of the problem of undiagnosed chronic kidney disease (CKD) and suggest that early identification and treatment will reduce the global burden of patients requiring dialysis. This has highlighted the twin problems of how to identify subjects for screening and target intervention to those with CKD most likely to progress to end-stage renal disease. Prospective studies have identified risk factors for CKD in the general population as well as risk factors for progression in patients with established CKD. Risk factors may thus be divided into initiating factors and perpetuating factors, with some overlap between the groups. In this paper, we review current data regarding CKD risk factors and illustrate how each may impact upon the mechanisms underlying CKD progression to accelerate loss of renal function. We propose that these risk factors should be used as a basis for developing a renal risk score, analogous to the Framingham risk score for ischemic heart disease, which will allow accurate determination of renal risk in the general population and among CKD patients.

Non-contrast-enhanced computerized tomography and analgesic-related kidney disease: report of the national analgesic nephropathy study

Previous studies suggested that the non-contrast-enhanced computerized tomography (CT) scan is a highly reliable tool for the diagnosis of analgesic-associated renal disease. However, this issue has not been addressed in the US population. A total of 221 incident patients with ESRD from different regions of the United States underwent a helical CT scan and detailed questioning about drug history. Specific renal anatomic criteria were developed to determine whether a constellation of CT findings (small indented calcified kidneys [SICK]) is linked to analgesic ingestion. For approximating use before the onset of renal disease, only analgesic ingestion at least 9 yr before starting dialysis was considered relevant. Fifteen patients met the criteria for SICK. This represented 7% of the enrolled patients and approximately 1% of the total ESRD population. There was a significant increase in the estimated risk among patients with a history of heavy aspirin ingestion (odds ratio [OR] 7.4 [95% confidence interval (CI) 1.2 to 43] for > or =1 kg lifetime; OR 8.8 [95% CI 1.2 to 66] for > or =0.3 kg/yr). Total analgesic ingestion of > or =0.3 kg/yr also was significantly associated with SICK (OR 8.2; 95% CI 1.5 to 45). These findings were accounted for largely by combination products that contained aspirin and phenacetin (used by three patients with SICK), which are no longer available. In addition, the CT finding of SICK was present only in a minority of heavy analgesic users, yielding a sensitivity of 5 to 26%. Findings of SICK are infrequent in the US ESRD population and do not occur among a sufficient proportion of heavy analgesic users to render the non-contrast-enhanced CT scan a sensitive tool to detect analgesic-associated kidney injury.

Case-control study on analgesics and nephropathy (SAN): protocol

Background

The association between intake of non-phenacetin-containing analgesics and the occurrence of chronic renal failure is still controversially discussed. A new epidemiologic study was planned and conducted in Germany and Austria.

Methods/design

The objective of the international, multicenter case-control study was to evaluate the association between end-stage renal disease (ESRD) and use of non-phenacetin-containing analgesics with particular emphasis on combined formulations. A targeted sample of 1000 new (incident) dialysis patients, aged less than 50 years, was planned to recruit between January 1, 2001 and December 31, 2004. The age limit was chosen to avoid contamination of the study population with phenacetin-containing analgesics to the extent possible. Four control subjects per ESRD case, matched by age, sex, and region were selected from the population living in the region the case came from.

Lifetime exposure to analgesics and potential renal risk factors were recorded in a single face-to-face interview. A set of aids was introduced to reinforce the memory of study participants.

A standardized, pre-tested interview questionnaire (participants), a medical documentation sheet (physicians in dialysis centres), a logbook for all activities (dialysis centres) were used to collect the necessary data.

Quality management consisted of the standardized procedures, (re-) training and supervision of interviewers, regular checks of all incoming data for completeness and plausibility.

The study is scientifically independent and governed by a international Scientific Advisory Committee that bridged the gap between the sponsoring companies and the investigators. Also other advisory groups assisted the managing committee of the study. All relevant German and Austrian nephrological associations supported the study, and the study design was carefully reviewed and approved by the Kidney Foundation of Germany.

Discussion

The study is expected to answer the main research question by end 2005. There is however a high potential for various biases that we tried to address with adequate measure. One limitation however cannot be overcome: The methodologically needed age-limitation of the study will make it not easy to generalize the results to age groups over 50 years. It might be suggested to repeat the study for persons over 50 years in 10 years when contamination with phenacetin use early in life is likely to be outgrown.

Role of Bcl-xL in paracetamol-induced tubular epithelial cell death

BACKGROUND

Paracetamol overdose causes acute renal failure and chronic exposure to paracetamol has been linked to chronic renal failure. Recently, apoptosis induction has been identified as a possible mechanism of paracetamol nephrotoxicity.

METHODS

Murine proximal tubular epithelial MCT cells were cultured in the presence of paracetamol. The effects of Bcl-xL overexpression, Bax antisense oligodeoxynucleotides, and different caspase inhibitors on cell death were studied.

RESULTS

While paracetamol did not change the mRNA expression of the antiapoptotic gene bcl-xL, it decreased Bcl-xL protein levels. The decrease in Bcl-xL was prevented by lactacystin, but not by caspase inhibitors. Addition to the culture media of the survival factors present in fetal calf serum (FCS) increased Bcl-xL expression and decreased paracetamol-induced apoptosis. Overexpression of a human bcl-xL transgene decreased apoptosis induced by paracetamol by 60% at 24 hours and increased long-term cell survival. The constitutive expression of the viral caspase inhibitor CrmA decreased the rate of apoptosis by 60% at 24 hours and the broad-specific caspase inhibitor zVAD-fmk prevented paracetamol-induced features of apoptosis. However, caspase inhibitors did not prevent eventual cell death. Bax did not translocate to mitochondria and Bax antisense oligodeoxynucleotides were not protective.

CONCLUSION

Our results suggest that induction of apoptosis may underlie the nephrotoxic potential of paracetamol and identify Bcl-xL as a player in toxic tubular cell injury.

Drug bioactivation, covalent binding to target proteins and toxicity relevance

A number of therapeutic drugs with different structures and mechanisms of action have been reported to undergo metabolic activation by Phase I or Phase II drug-metabolizing enzymes. The bioactivation gives rise to reactive metabolites/intermediates, which readily confer covalent binding to various target proteins by nucleophilic substitution and/or Schiff's base mechanism. These drugs include analgesics (e.g., acetaminophen), antibacterial agents (e.g., sulfonamides and macrolide antibiotics), anticancer drugs (e.g., irinotecan), antiepileptic drugs (e.g., carbamazepine), anti-HIV agents (e.g., ritonavir), antipsychotics (e.g., clozapine), cardiovascular drugs (e.g., procainamide and hydralazine), immunosupressants (e.g., cyclosporine A), inhalational anesthetics (e.g., halothane), nonsteroidal anti-inflammatory drugs (NSAIDSs) (e.g., diclofenac), and steroids and their receptor modulators (e.g., estrogens and tamoxifen). Some herbal and dietary constituents are also bioactivated to reactive metabolites capable of binding covalently and inactivating cytochrome P450s (CYPs). A number of important target proteins of drugs have been identified by mass spectrometric techniques and proteomic approaches. The covalent binding and formation of drug-protein adducts are generally considered to be related to drug toxicity, and selective protein covalent binding by drug metabolites may lead to selective organ toxicity. However, the mechanisms involved in the protein adduct-induced toxicity are largely undefined, although it has been suggested that drug-protein adducts may cause toxicity either through impairing physiological functions of the modified proteins or through immune-mediated mechanisms. In addition, mechanism-based inhibition of CYPs may result in toxic drug-drug interactions. The clinical consequences of drug bioactivation and covalent binding to proteins are unpredictable, depending on many factors that are associated with the administered drugs and patients. Further studies using proteomic and genomic approaches with high throughput capacity are needed to identify the protein targets of reactive drug metabolites, and to elucidate the structure-activity relationships of drug's covalent binding to proteins and their clinical outcomes.

Chinese herbal recipe versus diclofenac in symptomatic treatment of osteoarthritis of the knee: a randomized controlled trial [ISRCTN70292892]

Background

Duhuo Jisheng Wan (DJW) is perhaps the best known and most widely used Chinese herbal recipe for arthralgia, but the clinical study to verify its efficacy is lacking. The purpose of this study was to compare the efficacy of DJW versus diclofenac in symptomatic treatment of osteoarthritis (OA) of the knee.

Methods

This study was a randomized, double-blind, double-dummy, controlled trial. The 200 patients suffering from OA of the knee, were randomized into the DJW and diclofenac group. The patients were evaluated after a run-in period of one week (week 0) and then weekly during 4 weeks of treatment. The clinical assessments included visual analog scale (VAS) score that assessed pain and stiffness, Lequesne's functional index, time for climbing up 10 steps, as well as physician's and patients' overall opinions on improvement.

Results

Ninety four patients in each group completed the study. In the first few weeks of treatment, the mean changes in some variables (VAS, which assessed walking pain, standing pain and stiffness, as well as Lequesne's functional index) of the DJW group were significantly lower than those of the diclofenac group. Afterwards, these mean changes became no different throughout the study. Most of the physician's and patients' overall opinions on improvement at each time point did not significantly differ between the two groups. Approximately 30% of patients in both groups experienced mild adverse events.

Conclusion

DJW demonstrates clinically comparable efficacy to diclofenac after 4 weeks of treatment. However, the slow onset of action as well as approximately equal rate of adverse events to diclofenac might limit its alternative role in treatment of OA of the knee.

A population-based cohort study of mortality among adults prescribed paracetamol in Denmark

OBJECTIVE

We examined overall and cause-specific mortality in a population-based cohort of individuals prescribed paracetamol. We evaluated rates of death due to liver and renal disease, cancer, and other major causes of death.

METHOD

Using the population-based pharmacoepidemiology prescription database of North Jutland County, Denmark, we identified nearly 50,000 persons receiving prescriptions for paracetamol from 1989 to 1995 and evaluated mortality through 1996. Standardized mortality ratios (SMRs) for 18 specific causes of death were computed for persons prescribed paracetamol compared with persons among the general population of the county.

RESULTS

SMRs were elevated regardless of cause of death, with a nearly doubled overall death rate among persons prescribed paracetamol. The mortality ratios were highest within 1 year of paracetamol prescription and tended to decline with increasing follow-up, especially for cancers. The magnitudes of the excess mortality risks for liver and renal diseases were not materially higher than for other causes of death.

CONCLUSION

Paracetamol is a first-line analgesic for patients with a wide variety of chronic or serious illnesses and therefore is associated with increased rates of nearly all causes of death. The findings are an example of confounding by indication. Paracetamol may be a drug most prone to this form of bias in pharmacoepidemiologic studies. Future observational studies reporting adverse effects of paracetamol must thoroughly evaluate confounding by indication before making causal inferences.

Risk factors for progressive chronic kidney disease

The occurrence of chronic kidney disease and subsequent rate of loss of renal function are highly variable among individuals with the same underlying cause of renal injury or degree of functional impairment. Individual variability of risk is typical of complex diseases and reflects the multifactorial nature of the biologic mechanisms that are involved in the underlying disease process. The utility of the risk factor concept in developing CKD prevention and control strategies includes identifying individuals at high risk for the occurrence and progression of CKD, defining at-risk populations, elucidating potential targets for intervention, and generating explanatory hypotheses for the variable risk of CKD noted in different populations. Future application of the risk factor concept in the prevention and control of CKD will entail developing multivariate prediction equations; using spatial and temporal, as well as personal, characteristics, to define at-risk populations; identifying biomarkers for complex risk factors like race; and translating this information into testable interventions. This should include active extension of our current understanding of health care, social, and economic risk factors at both the individual and the community level.

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

Confounding by indication in epidemiologic studies of commonly used analgesics

Confounding by indication is a bias frequently encountered in observational epidemiologic studies of drug effects. Because the allocation of treatment in observational studies is not randomized and the indication for treatment may be related to the risk of future health outcomes, the resulting imbalance in the underlying risk profile between treated and comparison groups can generate biased results. Confounding by indication is often present in studies of drugs that are not widely prescribed, because the indications for their use are narrow and not likely to be present in comparison groups; however, this bias is also observed in the study of widely used over-the-counter and prescription drugs, are exemplified by studies of analgesics. In this article we review examples from the published literature to demonstrate how confounding by indication can affect the findings of pharmacoepidemiologic studies relating analgesic use to various health outcomes.

Acetaminophen, aspirin, and chronic renal failure

BACKGROUND

Several epidemiologic studies have demonstrated an association between heavy consumption of nonnarcotic analgesics and the occurrence of chronic renal failure, but it is unclear which is the cause and which is the effect

METHODS

In a nationwide, population-based, case-control study of early-stage chronic renal failure in Sweden, face-to-face interviews were conducted with 926 patients with newly diagnosed renal failure and 998 control subjects, of whom 918 and 980, respectively, had complete data. We used logistic-regression models to estimate the relative risks of disease-specific types of chronic renal failure associated with the use of various analgesics

RESULTS

Aspirin and acetaminophen were used regularly by 37 percent and 25 percent, respectively, of the patients with renal failure and by 19 percent and 12 percent, respectively, of the controls. Regular use of either drug in the absence of the other was associated with an increase by a factor of 2.5 in the risk of chronic renal failure from any cause. The relative risks rose with increasing cumulative lifetime doses, rose more consistently with acetaminophen use than with aspirin use, and were increased for most disease-specific types of chronic renal failure. When we disregarded the recent use of analgesics, which could have occurred in response to antecedents of renal disease, the associations were only slightly attenuated

CONCLUSIONS

Our results are consistent with the existence of exacerbating effects of acetaminophen and aspirin on chronic renal failure. However, we cannot rule out the possibility of bias due to the triggering of analgesic consumption by predisposing conditions.

Direct toxicity of nonsteroidal antiinflammatory drugs for renal medullary cells

Antipyretic analgesics, taken in large doses over a prolonged period, cause a specific form of kidney disease, characterized by papillary necrosis and interstitial scarring. Epidemiological evidence incriminated mixtures of drugs including aspirin (ASA), phenacetin, and caffeine. The mechanism of toxicity is unclear. We tested the effects of ASA, acetaminophen (APAF, the active metabolite of phenacetin), caffeine, and other related drugs individually and in combination on mouse inner medullary collecting duct cells (mIMCD3). The number of rapidly proliferating cells was reduced by approximately 50% by 0.5 mM ASA, salicylic acid, or APAF. The drugs had less effect on confluent cells, which proliferate slowly. Thus, the slow in vivo turnover of IMCD cells could explain why clinical toxicity requires very high doses of these drugs over a very long period. Caffeine greatly potentiated the effect of acetaminophen, pointing to a potential danger of the mixture. Cyclooxygenase (COX) inhibitors, indomethacin and NS-398, did not reduce cell number except at concentrations greatly in excess of those that inhibit COX. Therefore, COX inhibition alone is not toxic. APAF arrests most cells in late G(1) and S and produces a mixed form of cell death with both oncosis (swollen cells and nuclei) and apoptosis. APAF is known to inhibit the synthesis of DNA and cause chromosomal aberrations due to inhibition of ribonucleotide reductase. Such effects of APAF might account for renal medullary cell death in vivo and development of uroepithelial tumors from surviving cells that have chromosomal aberrations.

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.

Toxicities of drugs used in the management of fever

Fever is frequently managed outside the purview of medical professionals, and antipyretic therapy, on the whole, is generally considered safe. However, each of the drugs used in the management of fever has significant toxicities. The purpose of this review is to examine the relative safety of such agents with a focus on the nonsteroidal anti-inflammatory drugs and acetaminophen. Toxicity to the gastrointestinal, renal, and hepatic systems are considered; the comparative safety profile of acetaminophen and ibuprofen as antipyretics are highlighted; and specific recommendations to improve the safe use of these therapies are advanced.