Analgesic nephropathy: is it caused by multi-analgesic abuse or single substance use?

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.

[Is Concomitant Therapy with Acetaminophen and Low-dose Aspirin a Risk Factor for CKD Progression? A 6-Year Cohort Study]

Concomitant therapy with acetaminophen (APAP) and low-dose aspirin is often used in clinical settings; however, it is unclear whether this combination is involved in the progression of chronic kidney disease (CKD). We hypothesized that concomitant therapy with APAP and low-dose aspirin may cause CKD progression. We carried out a retrospective 6-year cohort study that included all patients who received low-dose aspirin from January 2011 to December 2016 at Kaetsu Hospital. Primary outcome was defined as CKD progression at the end of the study compared with baseline. Among the 441 patients treated during the study period, we identified 89 cases of CKD progression. Multivariate regression analysis showed that exposure to APAP>50 g [odds ratio (OR), 2.68, 95% confidence interval (CI), 1.08-6.70], age increase by 1 year (OR, 1.05, 95% CI, 1.02-1.08), and diabetes mellitus (OR, 2.40, 95% CI, 1.41-4.08) had positive associations with CKD progression. Our findings suggested that concomitant therapy with APAP and low-dose aspirin increased the risk of CKD progression. Therefore, we recommend more thorough monitoring of serum creatinine when patients are on such concomitant therapy. Moreover, it is important to advise users of low-dose aspirin to avoid unnecessary use of APAP, in order to reduce the risk of CKD progression.

Therapeutic Challenges to End-Stage Kidney Disease in a Patient with Tetralogy of Fallot

In this report, we describe the case of an end-stage kidney disease patient with tetralogy of Fallot (TOF). A 33-year-old female with TOF was admitted to our hospital with complaints of general fatigue and appetite loss probably due to uremic milieu. She was ultimately treated with peritoneal dialysis (PD) with a favorable clinical course. TOF patients with chronic kidney disease are not exceptional, although the currently available information regarding the association between TOF and renal failure severe enough to require dialysis treatment is limited. We also discuss the complex processes of how and why PD was selected as a mode of chronic renal replacement therapy in this case.

Normal black kidney

A black kidney has 3 major differential diagnoses: hemosiderosis, lipofuscin pigment and melanotic renal cell carcinoma. Excluding lipofuscin, the other 2 are accompanied by an abnormal renal function. We report on a 25-year-old man who intended to donate a kidney to his cousin. On the operating room table when we incised the left flank region and exposed the kidney, we found a firm and black kidney so the operation was cancelled due to potential vascular injuries. Days after the incomplete procedure, we reviewed the donor's biochemistry and imaging to reassess his renal function, but the results showed quite normal renal function again. The result of Ham test was also negative. Two weeks later, we began the operation, removed the same left kidney and found that it was in the same conditions as it was before. We took the opportunity to send needle biopsies of the kidney for histopathologic analysis. The analysis showed a melanotic kidney without pathological changes in glomeruli and interstitium and vessels. A black kidney may result in hemosiderin, lipofuscin or melanin deposits in the kidney, which can confirm the diagnosis; however, special tests for underlying disease and renal function should be considered. Some causes of black kidney lead to abnormal function, but our patients's kidney returned to normal.

The epidemiology of drug-induced disorders: the kidney

The epidemiology of drug-induced renal disorders is a complex topic. Drug-associated nephrotoxicity accounts for 18 - 27% of all acute kidney injury cases in US hospitals. Medications can affect all aspects of the kidney, and drugs that are associated with renal dysfunction are used commonly in clinical practice. The article reviews six major mechanisms of drug-induced renal dysfunction as well as lists the major medications involved. NSAIDs, aminoglycosides, amphotericin B and calcineurin inhibitors are just some examples of drugs that contribute to renal dysfunction. The medical community must be aware of patient risk factors for nephrotoxicity, as well as the drug's inherent nephrotoxic potential, when prescribing and administering medications.

Non-phenacetin analgesics and analgesic nephropathy: clinical assessment of high users from a case-control study

BACKGROUND

A recent large-scale case-control study on analgesic nephropathy (SAN) [1] found no increased risk of end-stage renal disease (ESRD) in users of combined or single formulations of phenacetin-free analgesics. In a subgroup of 22 high users, however, a dose-dependent increased risk was found, which raised the question if these patients presented or not with analgesic nephropathy (AN).

METHODS

The individual questionnaires of this subgroup of high users were reviewed, and the total lifetime intake of different types of analgesics was calculated. For evidence of AN, the following data were considered: (1) the amount and type of analgesics consumed, (2) the cause of ESRD, as diagnosed by the nephrologist in charge of the patient and (3) renal imaging and other relevant laboratory data.

RESULTS

This group of ESRD patients consumed on average 7.8 kg of antipyretic analgesics (range 30.8-2.7 kg) over an average of 21.5 years (range 35-6 years). Single analgesics were exclusively used by 12 patients (54.5%) and combined analgesics by 5 patients (22.7%), while 5 patients used both. None of the patients was diagnosed as having AN, and a review of the questionnaires did not disclose evidence suggestive of AN. The possibility that, irrespective of AN, the analgesic (ab)use contributed to the progression of existing renal diseases cannot be answered in the absence of well-defined criteria. The data supporting the existence of such an analgesic-associated nephropathy (AAN) are, however, not consistent and most likely due to confounding by indication.

CONCLUSION

In a group of ESRD patients with high use of non-phenacetin analgesics, no evidence of AN was found. There is no evidence that (ab)use of analgesics or NSAIDs other than phenacetin leads to a pathologically or clinically defined renal disease that could be named AN or AAN.

Development of a community pharmacy-based model to identify and treat OTC drug abuse/misuse: a pilot study

OBJECTIVE

The aim of this study was to develop and pilot a harm-minimisation model for the identification and treatment of over-the-counter (OTC) drug abuse/misuse by community pharmacists.

METHOD

Extensive consultation was conducted during the development of the model. This included an exploratory conference involving an interdisciplinary group of delegates and detailed individual consultation with a range of healthcare practitioners. Consultation with a psychologist specialising in communication skills allowed development of the communication aspects of the model. A comprehensive manual detailing the model was prepared.

RESULTS

The model is designed to be used by community pharmacists in conjunction with other healthcare professionals. It focuses on the abuse/misuse of opioids, laxatives and antihistamines and can be broadly divided into three phases, namely: patient identification and recruitment, treatment/referrals and data collection/outcome measurement. Client identification is via record-keeping which is implemented alongside an information campaign promoting safe use of OTC medicines. Once identified, the pharmacist aims to recruit clients using the developed communication strategies. Treatment depends on whether the problem is misuse or abuse and on the product. Several treatment paths are available including treatment according to an agreed protocol and referring to the GP or community addiction team (CAT). Two pharmacists were recruited and trained to pilot the model. Of the clients, 18 were identified as abusing/misusing OTC products over a one-month period. The subject of inappropriate OTC use was raised with 14 of these clients. Some success was noted in that clients agreed to stop using the product and/or to try safer alternatives. As expected, some sales had to be refused, as the client was unwilling to accept the pharmacist's intervention.

CONCLUSION

This study represents the first reported structured attempt by community pharmacists in the UK to address the abuse/misuse of OTC medication. Work is now ongoing to modify this model in light of the pilot study findings.

Treatment of pain in patients with renal insufficiency: The World Health Organization three-step ladder adapted

The World Health Organization established official recommendations for managing pain in cancer patients. Since then, this stepladder approach has been widely adopted as a conceptual framework to treat all types of pain. However, those guidelines have not been critically evaluated for use in patients with renal insufficiency. In these patients, the questions of drug dosage adjustment and renal toxicity must be considered. This article reviews the pharmacokinetics of major analgesic drugs and data on their use and/or behavior in renal failure and considers their potential nephrotoxicity. Finally, according to available data in the international literature on pharmacokinetics, recommendations for dosage adjustment in patients with renal failure, and their potential nephrotoxicity, the World Health Organization three-step ladder for the treatment of pain was modified and adapted for patients with impaired renal function. Perspective This well-known treatment strategy now adapted for use in patients with renal insufficiency should secure and rationalize pain treatment in those patients.

Cyclooxygenase-2 inhibition and renal physiology

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

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.