Renal effects of over-the-counter analgesics

Drug-induced peripheral oedema: An aetiology-based review

Many drugs are responsible, through different mechanisms, for peripheral oedema. Severity is highly variable, ranging from slight oedema of the lower limbs to anasarca pictures as in the capillary leak syndrome. Although most often noninflammatory and bilateral, some drugs are associated with peripheral oedema that is readily erythematous (eg, pemetrexed) or unilateral (eg, sirolimus). Thus, drug-induced peripheral oedema is underrecognized and misdiagnosed, frequently leading to a prescribing cascade. Four main mechanisms are involved, namely precapillary arteriolar vasodilation (vasodilatory oedema), sodium/water retention (renal oedema), lymphatic insufficiency (lymphedema) and increased capillary permeability (permeability oedema). The underlying mechanism has significant impact on treatment efficacy. The purpose of this review is to provide a comprehensive analysis of the main causative drugs by illustrating each pathophysiological mechanism and their management through an example of a drug.

Acute renal failure in CF patients chronically infected by the Liverpool epidemic Pseudomonas aeruginosa strain (LES)

Although acute renal failure has been described in children with CF in relation to intravenous aminoglycoside use, there are no reports in the adult CF literature. We describe 8 cases of acute renal failure in adult CF patients, all occurring during the use of intravenous aminoglycosides for the treatment of pulmonary exacerbations with an epidemic multi-resistant Pseudomonas aeruginosa strain. Potential contributory factors are discussed. These cases demonstrate another complication of infection by epidemic Pseudomonas strains in CF, and confirm the need for effective segregation policies to prevent this.

The role of paracetamol in chronic pain: an evidence-based approach

Chronic pain is a significant public health burden. Several international guidelines and influential reviews recommend the use of paracetamol (acetaminophen) as the first-line analgesic of choice for the management of chronic pain. These recommendations are based largely on the balance of evidence, which favorably demonstrates the efficacy, safety, and low cost of paracetamol relative to other analgesics.A decade ago, March et al suggested that because of the dangers associated with conventional nonsteroidal antiinflammatory (NSAID) use, particularly in the elderly, they should ideally not be used without an individual n-of-1 trial to show that they are more effective than paracetamol. Today, the results of our investigations into the individualization of pain management options continue to support this suggestion. Based on the data available to date, it still seems prudent to use NSAIDs only in those patients in whom there is good evidence of improved efficacy over paracetamol. In patients with chronic pain, paracetamol can play an important role as an NSAID sparer, with resultant benefits in terms of reduced adverse effects and cost savings.

The Use of NSAIDs and Nutritional Supplements in Athletes with Osteoarthritis: Prevalence, Benefits, and Consequences

The use of nonsteroidal antiinflammatory medications (NSAIDs) and nutraceuticals, such as glucosamine and chondroitin, is common among athletes at all ages and levels of participation. The use of these drugs has significant effects on pain and swelling associated with injury; however, this use does have significant risks to the gastrointestinal, hepatic, and renal organ systems. In the athlete with degenerative changes in the joints, the use of these medications can become chronic and lead to an increased risk of adverse effects. The purpose of this article is to examine the incidence of injury in sports, the prevalence of osteoarthritis in athletes, and the use of common over-the-counter medications and supplements. In addition, the mechanism of action, adverse side effects, and behavioral patterns for use of these medications will be analyzed.

Evaluation of hematuria in children

The detection of blood in a child's urine is alarming and often prompts many laboratory studies. Hematuria is one of the most important signs of renal or bladder disease, but proteinuria often is a more important diagnostic and prognostic finding. The physician should ensure that serious conditions are not overlooked, avoid unnecessary laboratory studies, reassure the family, and provide guidelines for additional studies if there is a change in the child's course. This article provides an approach to the evaluation and management of hematuria in a child. Many tests have been recommended for the child with hematuria, but no consensus exists on a systematic evaluation.

Hematuria in children

Children with hematuria require a thorough history and physical examination. Not all children with hematuria require the same investigations. The only laboratory test uniformly required for children with the various presentations of hematuria is a complete urinalysis with a microscopic examination. The rest of the evaluation is tailored according to the pertinent history, physical examination, and other abnormalities on the urinalysis. This article has provided a brief summary of the more common causes of pediatric hematuria and suggestions for tailoring the patient's evaluation according to the presentation. Most causes of hematuria in pediatrics represent medical conditions that often require referral to a pediatric nephrologist. Indications for referral to a urologist are more limited and include stones that do not pass spontaneously or are more than 5 mm in diameter, renal injury from trauma, anatomic abnormalities, or gross hematuria that seems to originate from the urinary tract and is without an identified cause.

Children and medicines: self-treatment of common illnesses among Luo schoolchildren in western Kenya

In a rural area of western Kenya, primary schoolchildren's health seeking behaviour in response to common illnesses was investigated. 57 primary schoolchildren (age 11-17 years, median 13 years) were interviewed weekly about their health status and health seeking activities for 30 weeks. The children each experienced on average 25 illness episodes during this period. Most episodes could be categorised into 4 groups: 'cold', 'headache', 'abdominal complaints' and 'injuries'. One fifth (21%) of the illness episodes were serious enough to keep the children from school. In 28% of them, an adult was consulted, while 72% were not reported to an adult caretaker. Of the episodes without adult involvement, 81% remained untreated, while 19% were treated by the children themselves with either herbal or Western medicines. Of all the medicines taken by the children, two thirds were provided or facilitated by adults (assisted treatment) and one third taken by the children themselves without adult involvement (self-treatment). Among boys, the proportion of illnesses, which were self-treated increased with age from 12% in the youngest age group (< 13 years) to 34% in the oldest (> 14 years). In girls, the proportion of illnesses which were self-treated was consistently lower than among boys and remained constant around 9% for all age groups. The proportion of Western pharmaceuticals used for self-treatment increased with age from 44% in the youngest age group to 63% in the oldest (average 52% Western pharmaceuticals). Again, there were differences between boys and girls: among the youngest age group, boys were twice as likely to use pharmaceuticals than girls (62 versus 32% of the self-treatments, respectively) and in the oldest age group they were nearly three times more likely (75 versus 25%, respectively). These differences in self-treatment practices and choice of medicines between girls and boys may reflect the higher income potential of boys, who can earn money by fishing. Pharmaceuticals were generally preferred for the treatment of headache and fevers, or colds, while herbal remedies were the preferred choice for the treatment of abdominal complaints and wounds. The most commonly used pharmaceuticals were antimalarials (mainly chloroquine), painkillers and antipyretics (mainly aspirin and paracetamol), which were stocked in most small shops in the village at low prices and readily sold to children. Throughout primary school age Kenyan children are growing into a pluralistic medical practice, integrating Western pharmaceuticals into the local herbal medical system, and gradually become autonomous agents in their health care.

Cyclooxygenase-deficient mice. A summary of their characteristics and susceptibilities to inflammation and carcinogenesis

Cyclooxygenase (COX)-1- and COX-2-deficient mice have unique physiological differences that have allowed investigation into the individual biological roles of the COX isoforms. In the following, the phenotypes of the two COX knockout mice are summarized, and recent studies to investigate the effects of COX deficiency on inflammatory responses and cancer susceptibility are discussed. The data suggest that both isoforms have important roles in the maintenance of physiological homeostasis and that such designations as house-keeping and/or response gene may not be entirely accurate. Furthermore, data from COX-deficient mice indicate that both isoforms can contribute to the inflammatory response and that both isoforms have significant roles in carcinogenesis.

Cyclooxygenase knockout mice: models for elucidating isoform-specific functions

The development of cyclooxygenase (COX) deficient mice has allowed investigation into the individual physiological roles of the COX-1 and COX-2 isoforms. In the following article, the phenotypes of the two Ptgs (genes coding for COX-1 and COX-2) knockouts are summarized, and recent studies to investigate the effects of COX deficiency on cancer susceptibility, inflammatory response, gastric ulceration, and female reproductive processes are discussed. Also, the development and potential uses of mice deficient in both COX isoforms and mice containing only a single copy of one isoform are discussed. Additionally, when the data permit, the effects of genetic ablation of COX activity are compared with those of pharmacological inhibition of COX activity by nonsteroidal anti-inflammatory drugs. The data suggest that prostaglandins derived via the individual COX isoforms have separate as well as common functions. However, for the maintenance of normal physiology, it appears that deficiency of COX-2 has more profound effects than deficiency of COX-1.

Effects of acetaminophen and ibuprofen on renal function in anesthetized normal and sodium-depleted dogs

In certain conditions, renal prostaglandins (PGs) are important determinants of kidney function. Under these "renal PG-dependent states," pharmacological inhibition of vasodilatory PG may result in excessive renal vasoconstriction and adversely affect kidney function. The purposes of this study were to determine whether acetaminophen (Acet), a weak PG-synthesis inhibitor, influences kidney function in the renal PG-dependent state of anesthesia and sodium depletion. Comparisons were made with ibuprofen (Ibu). Measurements of PGE2 excretion were used to assess renal PG synthesis. Acet (15 mg/kg) and Ibu (10 mg/kg) both decreased renal blood flow and glomerular filtration rate by approximately 20-30% in normal, anesthetized, sodium-replete dogs. Although Acet produced similar changes in renal blood flow and glomerular filtration rate in the low-sodium dogs, Ibu caused a significantly greater renal vasoconstriction (64 +/- 10%) in these animals. Both Acet and Ibu inhibited urinary PGE2 excretion in sodium-replete and low-sodium dogs. Ibu tended to have a greater and more prolonged effect than did Acet. These results suggest that Acet alters PGE2 excretion and kidney function under renal PG-dependent conditions; the effects, however, are less severe than those seen with Ibu.

A safety assessment of fixed combinations of acetaminophen and acetylsalicylic acid, coformulated with caffeine

Overuse and abuse of phenacetin-containing mixed analgesics has contributed to end-stage renal disease. Combination analgesics, especially those coformulated with caffeine, have been implicated as imparting a greater risk of analgesic-associated nephropathy (AAN) than single or coformulated analgesics without caffeine. This has led to a recommendation that the sale of "two plus caffeine" analgesic mixtures be reclassified from over-the-counter to prescription only availability. There is a rational basis for coformulating acetylsalicylic acid (ASA) and acetaminophen (paracetamol) as this reduces the dose of each, without altering efficacy. The coformulation of caffeine with these analgesics has a significant adjuvant effect and increases analgesic efficacy 1.4-1.6-fold. Currently available animal and human data do not support the notion that the nephrotoxic risk from coformulated ASA and acetaminophen is higher than the risk from either ASA or acetaminophen alone, in equivalent analgesic doses. There are no epidemiological data that implicate caffeine in AAN, and only limited evidence that links excessive acetaminophen usage to renal disease. There is no evidence that caffeine increases analgesics papillotoxicity directly. The presence of caffeine in mixtures of analgesics are no more addictive than other sources of caffeine. There is no evidence to suggest that adding caffeine to analgesic mixtures enhances the potential for promoting analgesic misuse in the general population. Thus distinct therapeutic benefits of ASA, acetaminophen and caffeine appear to outweigh any known risk. It is doubtful if preventing the availability of these products will significantly affect the role of analgesic abuse/overuse in end-stage renal disease. Better risk management would come from a focused educational program, developed in a close collaboration between industry, healthcare professionals and consumer organizations, such a program must warn against the potential dangers of analgesic and non-steroidal anti-inflammatory drug misuse.

Renal papillary necrosis--40 years on

Analgesics and nonsteroidal anti-inflammatory drugs (NSAIDs) are well recognized as a major class of therapeutic agent that causes renal papillary necrosis (RPN). Over the last decade a broad spectrum of other therapeutic agents and many chemicals have also been reported that have the potential to cause this lesion in animals and man. There is consensus that RPN is the primary lesion that can progress to cortical degeneration; and it is only at this stage that the lesion is easily diagnosed. In the absence of sensitive and selective noninvasive biomarkers of RPN there is still no clear indication of which compound, under what circumstances, has the greatest potential to cause this lesion in man. Attempts to mimic RPN in rodents using analgesics and NSAIDs have not provided robust models of the lesion. Thus, much of the research has concentrated on those compounds that cause an acute or subacute RPN as the basis by which to study the pathogenesis of the lesion. Based on the mechanistic understanding gleaned from these model compounds it has been possible to transpose an understanding of the underlying processes to the analgesics and NSAIDs. The mechanism of RPN is still controversial. There are data that support microvascular changes and local ischemic injury as the underlying cause. Alternatively, several model papillotoxins, some analgesics, and NSAIDs target selectively for the medullary interstitial cells, which is the earliest reported aberration, after which there are a series of degenerative processes affecting other renal cell types. Many papillotoxins have the potential to undergo prostaglandin hydroperoxidase-mediated metabolic activation, specifically in the renal medullary interstitial cells. These reactive intermediates, in the presence of large quantities of polyunsaturated lipid droplets, result in localized and selective injury of the medullary interstitial cells. These highly differentiated cells do not repair, and it is generally accepted that continuing insult to these cells will result in their progressive erosion. The loss of these cells is thought to be central to the degenerative cascade that affects the cortex. There is still a need to understand better the primary mechanism and the secondary consequences of RPN so that the risk of chemical agents in use and novel molecules can be fully assessed.

Normal ultrastructure of the kidney and lower urinary tract

The mammalian urinary tract includes the kidneys, ureters, urinary bladder, and urethra. The renal parenchyma is composed of the glomeruli and a heterogeneous array of tubule segments that are specialized in both function and structure and are arranged in a specific spatial distribution. The ultrastructure of the glomeruli and renal tubule epithelia have been well characterized and the relationship between the cellular structure and the function of the various components of the kidney have been the subject of intense study by many investigators. The lower urinary tract, the ureters, urinary bladder, and urethra, which are histologically similar throughout, are composed of a mucosal layer lined by transitional epithelium, a tunica muscularis, and a tunica serosa or adventitia. The present manuscript reviews the normal ultrastructural morphology of the kidney and the lower urinary tract. The normal ultrastructure is illustrated using transmission electron microscopy of normal rat kidney and urinary bladder preserved by in vivo perfusion with glutaraldehyde fixative and processed in epoxy resin.

Non-steroidal anti-inflammatory drug-induced renal failure: a brief review of the role of cyclo-oxygenase isoforms

Non-steroidal anti-inflammatory drugs are efficacious treatments for rheumatoid arthritis and osteoarthritis. However, an adverse effect of treatment with non-steroidal anti-inflammatory drugs is acute renal failure, particularly in a subset of patients that are in a state of effective volume depletion. The frequency of this side-effect in the general treated population is not known, but is probably less than 1% per year. Non-steroidal anti-inflammatory drugs act by inhibiting the synthesis of prostaglandins, which are important mediators of renal function. In the volume-depleted state prostaglandins may counter the vasoconstriction associated with the activation of the renin-angiotensin system. Cyclooxygenase is the rate-limiting enzyme involved in the synthesis of prostaglandins. Cyclooxygenase exists in two forms: a constitutive form (cyclooxygenase-1) and an inducible form (cyclooxygenase-2), which is associated with inflammation. Non-steroidal anti-inflammatory drugs are non-specific inhibitors of both forms of cyclooxygenase. New data are emerging regarding the role of cyclooxygenase-2 in the control of renal function. In normal rat and dog kidney, cyclooxygenase-2 is sparsely expressed in the macula densa, but expression is upregulated when animals are volume depleted. This review explores the possible role of cyclooxygenase-2 in the maintenance of normal renal function in volume depleted states.

Acute renal failure in infants, children and adults

Acute renal failure (ARF) occurs in many critically ill patients regardless of age. A combination of events often seen in critical care settings, including shock, sepsis, hypoxia, and the use of potentially nephrotoxic medications, combine to make ARF an ongoing and important management issue in critical care medicine. Since the events leading to the development of ARF differ in infants, children, adults, and the elderly, the pathophysiology, clinical features, and treatment modalities do indeed have remarkable similarities among the different age groups.

Nonsteroidal anti-inflammatory drugs, traditional opioids, and tramadol: contrasting therapies for the treatment of chronic pain

The treatment of chronic pain is an important function of physicians. In the United States, available drug treatments for chronic pain currently include simple analgesics such as acetaminophen, salicylates and other nonsteroidal anti-inflammatory drugs, traditional opioid drugs, and adjuvant agents (eg, antidepressants, anticonvulsants). Typically, the choice of a drug is made by balancing the indications for treatment, the clinical efficacy of the drug, and its toxicity. An understanding of the mechanism of action of these drugs helps to establish their role in therapy. Tramadol is an effective analgesic that works through a combined mechanism of weak mu receptor binding and the inhibition of serotonin and norepinephrine reuptake. Tramadol has a favorable adverse-effect profile and therefore is likely to have an important role in the management of chronic pain syndromes.

Dilemmas in the treatment of chronic pain

Chronic pain affects millions of people and results in activity limitations and psychologic and social problems. Even with the armamentarium of analgesics currently available, patients continue to receive inadequate relief of their painful conditions. One of the primary factors that limits appropriate utilization of analgesics is the spectrum of adverse effects that often results following acute and chronic use. In addition, legal and regulatory barriers, inability of physicians and other healthcare professionals to accurately assess pain, societal attitudes toward selected classes of pain medications, and other factors complicate pain management. Understanding how these barriers contribute to the undertreatment of pain and incorporating effective pharmacologic and nonpharmacologic measures into a treatment plan are required to manage patients with chronic pain.

Nonrenal toxicities of acetaminophen, aspirin, and nonsteroidal anti-inflammatory agents

Approximately 2% of the United States population consumes an analgesic, antipyretic, or nonsteroidal antiinflammatory drug (NSAID) each day. Aspirin and acetaminophen have been available to the public without a prescription (over-the-counter) for decades, while most NSAIDs are still only available with a prescription from a physician. The recent trend of switching NSAIDs from prescription to over-the-counter status may be perceived by some as an indication of their inherent safety. However, all these agents have been associated with a unique but overlapping safety profile. In fact, significant adverse events (AEs) on multiple organ systems, including the kidney and gastrointestinal tract, have been reported with most of these agents. In this review, the incidence of the nonrenal AEs of aspirin, acetaminophen, and selected NSAIDs are tabulated. The strengths of the causative associations are highlighted, the relative risks for the gastrointestinal and cardiovascular AEs are discussed, and the relationship to patient risk factors and drug characteristics, such as dose and half-life, are reviewed. The selection of the optimal agent for an individual patient depends on the balance between the desired pharmacodynamic response, the patient's pharmacotherapy history, and the degree of AE risk one is willing to accept. Therapy should be initiated in all settings with the lowest possible dosage since the incidence of the major AEs is dose related.