Renal effects of cyclooxygyenase-2-selective inhibitors

Use of metamizole and other non-opioid analgesics in Switzerland between 2014 and 2019: an observational study using a large health insurance claims database

OBJECTIVE

To investigate claims patterns for metamizole and other non-opioid analgesics in Switzerland. To characterise users of these non-opioid analgesics regarding sex, age, comedications and canton of residence.

METHODS

We conducted a retrospective descriptive study using administrative claims data of outpatient prescribed non-opioid analgesics of the Swiss health insurance company Helsana between January 2014 and December 2019. First, we evaluated the number of claims and defined daily doses  per year of metamizole, ibuprofen, diclofenac and paracetamol in adults aged 18 years or over. Second, we characterised new users of these non-opioid analgesics in terms of sex, age, claimed comedications and canton of residence.

RESULTS

From 2014 to 2019, among the investigated non-opioid analgesics, metamizole showed the highest increase in claims (+9545 claims, +50%) and defined daily doses (+86,869 defined daily doses, +84%) per 100,000 adults. Metamizole users had the highest median age (62 years [IQR: 44-77]) compared to ibuprofen (47 years [IQR: 33-62]), diclofenac (57 years [IQR: 43-71]) and paracetamol (58 years [IQR: 39-75]) users. Metamizole users also more frequently claimed proton pump inhibitors, anticoagulants, platelet aggregation inhibitors and antihypertensive drugs than users of other non-opioid analgesics. While metamizole was most frequently claimed in German-speaking regions of Switzerland, ibuprofen and paracetamol were most frequently claimed in the French-speaking regions and diclofenac in German- and Italian-speaking regions.

CONCLUSION

In Switzerland, metamizole was increasingly claimed between 2014 and 2019. Metamizole was most frequently claimed by older adults and patients with comedications suggestive of underlying conditions, which can be worsened or caused by use of nonsteroidal anti-inflammatory drugs. The lack of studies regarding the effectiveness and safety of metamizole in this population warrants further investigation.

Targeting Glomerular Hemodynamics for Kidney Protection

The kidney microcirculation is a unique structure as it is composed to 2 capillary beds in series: the glomerular and peritubular capillaries. The glomerular capillary bed is a high-pressure capillary bed, having a 60 mm Hg to 40 mm Hg pressure gradient, capable of producing an ultrafiltrate of plasma quantified as the glomerular filtration rate (GFR), thereby allowing for waste products to be removed and establishing sodium/volume homeostasis. Entering the glomerulus is the afferent arteriole, and the exiting one is the efferent arteriole. The concerted resistance of each of these arterioles is what is known as glomerular hemodynamics and is responsible for increasing or decreasing GFR and renal blood flow. Glomerular hemodynamics play an important role in how homeostasis is achieved. Minute-to-minute fluctuations in the GFR are achieved by constant sensing of distal delivery of sodium and chloride in the specialized cells called macula densa leading to upstream alternation in afferent arteriole resistance altering the pressure gradient for filtration. Specifically, 2 classes of medications (sodium glucose cotransporter-2 inhibitors and renin-angiotensin system blockers) have shown to be effective in long-term kidney health by altering glomerular hemodynamics. This review will discuss how tubuloglomerular feedback is achieved, and how different disease states and pharmacologic agents alter glomerular hemodynamics.

Carvacrol exerts nephroprotective effect in rat model of diclofenac-induced renal injury through regulation of oxidative stress and suppression of inflammatory response

Diclofenac (DIC) is an NSAID that can cause toxic effects in animals and humans and carvacrol (CAR) is a monoterpene compound that displays effective pharmacological and biological actions. The purpose of this work was to assess the influences of CAR on DIC-induced renal injury and oxidative stress in male rats. The rats were segregated into four groups. Group 1, control group; Group 2 received DIC-only; Groups 3, received CAR-only and group 4 received DIC plus CAR. Changes in biochemical indexes, pathological changes, molecular biological indexes, and genes related to the inflammation of main organs were evaluated. The results of this work indicated that the amounts of the serum protein carbonyl, sGOT, sGPT, urea, creatinine, uric acid, nitrite content, MDA, serum TNF-α, and renal TNF-α gene expression were remarkably increased and the levels of the GPx, GSH, CAT, and SOD were significantly reduced in DIC-only treated animals compared to the control group. On the other hand, treatment with CAR after exposure to DIC led to significant improvements in abnormalities of DIC-induced renal injury and serum biochemical factors. The data approve that CAR diminished the deleterious effects of DIC exposure. In this regard, the findings of this study indicated that the administration of CAR could alleviate the noxious effects of DIC on the antioxidant defense system and renal tissue.

Kolaviron Diminishes Diclofenac-Induced Liver and Kidney Toxicity in Wistar Rats Via Suppressing Inflammatory Events, Upregulating Antioxidant Defenses, and Improving Hematological Indices

Diclofenac (DF) is widely used in the treatment of pain and fever. Despite it therapeutic benefits, it triggered hepatorenal injury. Thus, the present study investigated the protective roles of kolaviron (KV) against DF-induced hepatic and renal toxicity in rats. The rats were allotted into groups: control group received propylene glycol and treatment groups received DF, which induced hepatorenal toxicity in rats and different doses of KV that prevented systemic toxicity of DF in rats. Twenty-four hours after the last treatment, all the rats were killed. Pro-inflammatory levels, markers of liver and kidney functions, oxidative stress, hematological indices, and histopathological alterations were evaluated. Diclofenac caused significant increase in the plasma levels of creatinine and urea and activities of liver enzymes, including bilirubin level, pro-inflammatory markers, and plasma prostaglandin E₂ (PGE₂). It also caused significant alteration in renal and hepatic PGE₂, antioxidants, lipid peroxidation (malondialdehyde), and hematological indices. These toxic effects were confirmed by histological studies and levels of inflammatory infiltration (myeloperoxidase). However, KV significantly prevented or reduced the adverse effects of DF in the plasma, liver, and kidney of the rats pretreated with KV before DF administration. This study showed the efficacy of KV as hepatic and renal protector in DF-induced hepatorenal toxicity through reduction of oxidative stress and suppression of inflammation.

Ameliorative effects of N-acetyl cysteine on diclofenac-induced renal injury in male rats based on serum biochemical parameters, oxidative biomarkers, and histopathological study

Diclofenac (DIC) can cause nephrotoxicity in humans. In this study, we evaluated the protective effects of N-acetyl cysteine (NAC) on DIC-induced nephrotoxicity. Rats were assigned to four groups. Group 1 was control group; group 2 administrated with DIC only; group 3 administrated with DIC plus NAC and group 4 was treated with DIC and silymarin. Then, the oxidative biomarkers in serum and kidney were evaluated. In group 2, DIC caused a remarkable elevation (p < 0.05) in the levels of serum uric acid, TNF-α, creatinine, urea, GOT, and GPT, protein carbonyl, malondialdehyde (MDA), and renal TNF-α gene expression, relative to control group. In treated groups with NAC and silymarin, a noticeable reduction (p < 0.05) was seen in mentioned levels of biochemical parameters. NAC showed that it could reduce the abnormality of biochemical parameters and histopathological changes which is induced by DIC. PRACTICAL APPLICATIONS: N-acetyl cysteine (NAC) has a potential to ameliorate renal histopathological changes and improving renal activity of antioxidant enzymes in nephrotoxicity by diclofenac. Also, NAC has a potential to reduce inflammatory gene expression in the diclofenac-induced nephrotoxicity. Additionally, NAC can be considered as an antioxidant which reduces renal MDA and serum protein carbonyl due to nephrotoxicity by diclofenac.

Natural remedies for non-steroidal anti-inflammatory drug-induced toxicity

The liver is an important organ of the body, which has a vital role in metabolic functions. The non-steroidal anti-inflammatory drug (NSAID), diclofenac causes hepato-renal toxicity and gastric ulcers. NSAIDs are noted to be an agent for the toxicity of body organs. This review has elaborated various scientific perspectives of the toxicity caused by diclofenac and its mechanistic action in affecting the vital organ. This review suggests natural products are better remedies than current clinical drugs against the toxicity caused by NSAIDs. Natural products are known for their minimal side effects, low cost and availability. On the other hand, synthetic drugs pose the danger of adverse effects if used frequently or over a long period. Copyright © 2016 John Wiley & Sons, Ltd.

Physiology and pathophysiology of cyclooxygenase-2 and prostaglandin E2 in the kidney

The cyclooxygenase (COX) enzyme system is the major pathway catalyzing the conversion of arachidonic acid into prostaglandins (PGs). PGs are lipid mediators implicated in a variety of physiological and pathophysiological processes in the kidney, including renal hemodynamics, body water and sodium balance, and the inflammatory injury characteristic in multiple renal diseases. Since the beginning of 1990s, it has been confirmed that COX exists in 2 isoforms, referred to as COX-1 and COX-2. Even though the 2 enzymes are similar in size and structure, COX-1 and COX-2 are regulated by different systems and have different functional roles. This review summarizes the current data on renal expression of the 2 COX isoforms and highlights mainly the role of COX-2 and PGE2 in several physiological and pathophysiological processes in the kidney.

Avian scavengers and the threat from veterinary pharmaceuticals

Veterinary use of the non-steroidal anti-inflammatory drug diclofenac on domesticated ungulates caused populations of resident Gyps vultures in the Indian sub-continent to collapse. The birds died when they fed on carrion from treated animals. Veterinary diclofenac was banned in 2006 and meloxicam was advocated as a 'vulture-safe' alternative. We examine the effectiveness of the 2006 ban, whether meloxicam has replaced diclofenac, and the impact of these changes on vultures. Drug residue data from liver samples collected from ungulate carcasses in India since 2004 demonstrate that the prevalence of diclofenac in carcasses in 2009 was half of that before the ban and meloxicam prevalence increased by 44%. The expected vulture death rate from diclofenac per meal in 2009 was one-third of that before the ban. Surveys at veterinary clinics show that diclofenac use in India began in 1994, coinciding with the onset of rapid Gyps declines ascertained from measured rates of declines. Our study shows that one pharmaceutical product has had a devastating impact on Asia's vultures. Large-scale research and survey were needed to detect, diagnose and quantify the problem and measure the response to remedial actions. Given these difficulties, other effects of pharmaceuticals in the environment may remain undetected.

Evidence that links loss of cyclooxygenase-2 with increased asymmetric dimethylarginine: novel explanation of cardiovascular side effects associated with anti-inflammatory drugs

Supplemental Digital Content is available in the text.

Background—

Cardiovascular side effects associated with cyclooxygenase-2 inhibitor drugs dominate clinical concern. Cyclooxygenase-2 is expressed in the renal medulla where inhibition causes fluid retention and increased blood pressure. However, the mechanisms linking cyclooxygenase-2 inhibition and cardiovascular events are unknown and no biomarkers have been identified.

Methods and Results—

Transcriptome analysis of wild-type and cyclooxygenase-2^−/− mouse tissues revealed 1 gene altered in the heart and aorta, but >1000 genes altered in the renal medulla, including those regulating the endogenous nitric oxide synthase inhibitors asymmetrical dimethylarginine (ADMA) and monomethyl-l-arginine. Cyclo-oxygenase-2^−/− mice had increased plasma levels of ADMA and monomethyl-l-arginine and reduced endothelial nitric oxide responses. These genes and methylarginines were not similarly altered in mice lacking prostacyclin receptors. Wild-type mice or human volunteers taking cyclooxygenase-2 inhibitors also showed increased plasma ADMA. Endothelial nitric oxide is cardio-protective, reducing thrombosis and atherosclerosis. Consequently, increased ADMA is associated with cardiovascular disease. Thus, our study identifies ADMA as a biomarker and mechanistic bridge between renal cyclooxygenase-2 inhibition and systemic vascular dysfunction with nonsteroidal anti-inflammatory drug usage.

Conclusions—

We identify the endogenous endothelial nitric oxide synthase inhibitor ADMA as a biomarker and mechanistic bridge between renal cyclooxygenase-2 inhibition and systemic vascular dysfunction.

Therapeutic effect of irradiation of magnetic infrared laser on osteoarthritis rat model

Osteoarthritis (OA) is a degenerative joint disease caused by articular cartilage loss. Many complementary and alternative medicines for OA have been reported so far, but the effectiveness is controversial. Previously, we have shown anti-inflammatory effects of low level laser therapy with static magnetic field, magnetic infrared laser (MIL), in various animal models. Therefore, the beneficial effects were examined in OA rat model. Rats were divided by six groups; no treatment controls of sham and OA model, three MIL treatment groups of OA model at 6.65, 2.66 and 1.33 J cm(-2), and Diclofenac group of OA model with 2 mg kg(-1) diclofenac sodium. The OA control exhibited typical symptoms of OA, but 4-week MIL treatment improved the functional movement of knee joint with reduced edematous changes. In addition, cartilage GAGs were detected more in all MIL treatment groups than OA control. It suggests that 4-week MIL irradiation has dose-dependent anti-inflammatory and chondroprotective effects on OA. Histopathological analyses revealed that MIL treatment inhibits the cartilage degradation and enhances chondrocyte proliferation. The fact that MIL has an additional potential for the cartilage formation and no adverse effects can be regarded as great advantages for OA treatment. These suggest that MIL can be useful for OA treatment.

Perioperative pain management in the neurosurgical patient

Perioperative pain management in neurosurgical patients has been inadequately recognized and treated. An increased awareness of pain management and advances in understanding of pain modulation and pathophysiology have led to improved perioperative care of patients. There is a need to assess neurologic function while providing superior analgesia with minimal side effects. Several classes of drugs are currently available or under investigation for use as adjuvants or alternative therapies. There remains a need to determine the best treatment of perioperative pain in this patient population. Improved awareness, assessment, and treatment of pain result in better care and overall patient outcome.

The association between nonsteroidal anti-inflammatory drugs and potassium concentrations: A pharmacoepidemiological study in Saudi Arabia

OBJECTIVE

Several nonsteroidal anti-inflammatory drugs (NSAIDs) have been linked to cardiac death. The mechanism that is responsible for this adverse effect appears to be ischemic insult; however, another possible mechanism involves hyperkalemia. The objective of the present study was to determine the feasibility of conducting pharmacoepidemiological studies in Saudi Arabia using refill prescription data to investigate the association between NSAIDs and increased serum potassium concentrations.

METHODS

This retrospective cohort study included patients from an academic medical center in Riyadh, Saudi Arabia. The patients who were recently prescribed NSAIDs were compared to a control group of paracetamol users, with respect to the drugs' effects on serum potassium concentrations. The covariates that affected the potassium concentration or the use of NSAIDs were controlled for in the analysis. The studied outcome was the first serum potassium concentration of more than 5 mEq/L.

RESULTS

A total of 184 patients were prescribed NSAIDs (n = 101) or paracetamol (n = 83) and met the inclusion criteria. Compared to the control group, the patients who received NSAIDs were more likely to be women, were less likely to use angiotensin-converting enzyme inhibitors, and were more likely to have lower baseline serum creatinine concentrations. The other baseline characteristics were similar between the patients in the NSAID group and the patients who received paracetamol. Compared to the patients who were prescribed paracetamol, those who were prescribed NSAIDs did not have an increased risk of hyperkalemia (odds ratio, 1.1, 95% confidence interval, 0.17-6.7, P = 0.95).

CONCLUSION

In the present, small feasibility study, no increase in the risk of hyperkalemia was associated with NSAIDs compared to paracetamol. The present study was exploratory and included only a small number of patients; therefore, this study may not be sufficiently powered to detect small differences between the groups. Future studies with larger sample sizes are needed to investigate the association between NSAIDs and hyperkalemia.

Risk of hyperkalemia associated with selective COX-2 inhibitors

BACKGROUND

Selective cyclooxygenase-2 (COX-2) inhibitors have been linked to cardiac death. The mechanism for this adverse effect appears to be by ischemic insult; however another mechanism could involve hyperkalemia. The objective of this study was to determine the effects of selective COX-2 inhibitors and non-selective nonsteroidal anti-inflammatory drugs (NSAIDs) on serum potassium concentration and the electrocardiogram.

METHODS

A retrospective cohort study was conducted using propensity score matching of patients from an inner-city academic medical center at Indianapolis, Indiana. Two hundred and two patients prescribed selective COX-2 inhibitors were matched to 202 patients prescribed non-selective NSAIDs using propensity scores methods. Outcomes included change in serum potassium concentration from baseline and the risk of an abnormal electrocardiogram.

RESULTS

Compared to patients prescribed non-selective NSAIDs, those prescribed a selective COX-2 inhibitor had a higher risk of serum potassium increase greater than 5 mEq/L (OR, 2.56; 95%CI, 1.03-6.36). However, patients prescribed selective COX-2 inhibitors had no greater risk of electrocardiogram abnormality (OR, 1.16; 95%CI, 0.74-1.82).

CONCLUSIONS

Selective COX-2 inhibitors may have a greater risk of hyperkalemia than non-selective NSAIDs. This study was exploratory with small numbers of patients. Further studies are needed to confirm these results and any association with cardiovascular events.

Gastric anti-ulcerative and anti-inflammatory activity of metyrosine in rats

In this study, the anti-inflammatory and anti-ulcerative effects of metyrosine, a selective tyrosine hydroxylase enzyme inhibitor, were investigated in rats. For ulcer experiments, indomethacin-induced gastric ulcer tests and ethanol-induced gastric ulcer tests were used. For these experiments, rats were fasted for 24 h. Different doses of metyrosine and 25 mg/kg doses of ranitidine were administered to rats, followed by indomethacin at 25 mg/kg for the indomethacin-induced ulcer test, or 50% ethanol for the ethanol-induced test. Results have shown that at all of the doses used (50, 100 and 200 mg/kg), metyrosine had significant anti-ulcerative effects in both indomethacin and ethanol-induced ulcer tests. Metyrosine doses of 100 and 200 mg/kg (especially the 200 mg/kg dose) also inhibited carrageenan-induced paw inflammation even more effectively than indomethacin. In addition, to characterize the anti-inflammatory mechanism of metyrosine we investigated its effects on cyclooxygenase (COX) activity in inflammatory tissue (rat paw). The results showed that all doses of metyrosine significantly inhibited high COX-2 activity. The degree of COX-2 inhibition correlated with the increase in anti-inflammatory activity. In conclusion, we found that metyrosine has more anti-inflammatory effects than indomethacin and that these effects can be attributed to the selective inhibition of COX-2 enzymes by metyrosine. We also found that adrenalin levels are reduced upon metyrosine treatment, which may be the cause of the observed gastro-protective effects of this compound.

Diclofenac, a Non-steroidal Anti-inflammatory Drug, Inhibits L-type Ca Channels in Neonatal Rat Ventricular Cardiomyocytes

A non-steroidal anti-inflammatory drug (NSAID) has many adverse effects including cardiovascular (CV) risk. Diclofenac among the nonselective NSAIDs has the highest CV risk such as congestive heart failure, which resulted commonly from the impaired cardiac pumping due to a disrupted excitation-contraction (E-C) coupling. We investigated the effects of diclofenac on the L-type calcium channels which are essential to the E-C coupling at the level of single ventricular myocytes isolated from neonatal rat heart, using the whole-cell voltage-clamp technique. Only diclofenac of three NSAIDs, including naproxen and ibuprofen, significantly reduced inward whole cell currents. At concentrations higher than 3 microM, diclofenac inhibited reversibly the Na(+) current and did irreversibly the L-type Ca(2+) channels-mediated inward current (IC(50)=12.89+/-0.43 microM) in a dose-dependent manner. However, nifedipine, a well-known L-type channel blocker, effectively inhibited the L-type Ca(2+) currents but not the Na(+) current. Our finding may explain that diclofenac causes the CV risk by the inhibition of L-type Ca(2+) channel, leading to the impairment of E-C coupling in cardiac myocytes.

Role of oxidative stress in celecoxib-induced renal damage in wistar rats

Celecoxib, a selective cyclo-oxygenase-2 (Cox-2) inhibitor, prevents the formation of prostaglandins, responsible for maintenance of renal function. Celecoxib administration may lead to renal damage. Since free radicals and antioxidant mechanisms play a significant role in renal injury; this study was designed to evaluate the role of oxidative stress in celecoxib-induced renal damage. The administration of celecoxib resulted in moderate and mild tubulointerstitial nephritis in chronic and acute group. The renal function tests were significantly altered only in the chronic group. The results in both the acute and the chronic group showed (1) a significant increase in the lipid peroxidation and in the activities of superoxide dismutase, catalase and glutathione-S-transferase and (2) a decrease in nitrite, reactive thiols and glutathione. In conclusion, our study suggests that chronic administration of celecoxib may have a damaging effect on kidney, as evident through altered histopathology and renal functions. This damage may be mediated by oxidative stress.

Perioperative pain management in the neurosurgical patient

The perioperative management of pain in neurosurgical patients is a controversial topic with management decisions based mainly on reports of anecdotal experiences. There is no consensus regarding the standardization of pain control in this patient population. In the last decade, improved awareness and advances in the practice of pain management have resulted in the implementation of diverse techniques to achieve adequate analgesia in this undertreated group of patients. This article provides information about the various techniques and approaches, based on the latest research and clinical trials conducted in this patient population. Specifically, the physiology of pain in patients undergoing brain or spine surgery, the different modalities for pain control, and the diverse choice of drugs, with their associated risks and benefits, are reviewed.

NSAIDs and scavenging birds: potential impacts beyond Asia's critically endangered vultures

Veterinary treatment of livestock with diclofenac, a non-steroidal anti-inflammatory drug (NSAID), has caused catastrophic declines of Gyps vultures in Asia. This has highlighted a lack of knowledge on the potential impacts of NSAIDs on scavenging birds. Surveys of veterinarians and zoos document the outcomes of the treatment of over 870 scavenging birds from 79 species. As well as diclofenac, carprofen and flunixin were associated with mortality, with deaths observed in 13 and 30% of cases, respectively. Mortality was also found following treatment with ibuprofen and phenylbutazone. NSAID toxicity was reported for raptors, storks, cranes and owls, suggesting that the potential conservation impact of NSAIDs may extend beyond Gyps vultures and could be significant for New World vultures. In contrast, there were no reported mortalities for the NSAID meloxicam, which was administered to over 700 birds from 60 species. The relative safety of meloxicam supports other studies indicating the suitability of this NSAID to replace diclofenac in Asia.

Extent of renal effect of cyclo-oxygenase-2-selective inhibitors is pharmacokinetic dependent

Non-steroidal anti-inflammatory drugs (NSAIDs) cause renal side-effects. In the present study, we tested the hypothesis that the extent of the renal effects of cyclo-oxygenase (COX)-2-selective NSAIDs is linked to their pharmacokinetics. A single oral dose of rofecoxib (10 mg/kg), celecoxib (40 mg/kg), meloxicam (3 mg/kg) or placebo was administered to rats. Urinary excretion of electrolytes, a marker of renal effects, and plasma and kidney concentrations of NSAIDs were measured. Rofecoxib and celecoxib, but not meloxicam, significantly decreased urinary sodium and potassium excretion. There was a significant correlation between the area under the 24 h plasma concentration-time curve (AUC0-24) of rofecoxib and the change in sodium (r = -0.65; P < 0.02) and potassium (r = -0.82; P < 0.0006) excretion. The AUC0-24 of celecoxib was correlated with sodium (r = -0.80; P < 0.05) but not potassium excretion. The ratios of kidney to plasma drug concentrations were 1.72, 3.16 and 0.17 for rofecoxib, celecoxib and meloxicam, respectively. The renal effect of the COX-2-selective NSAIDs examined, marked by their ability to reduce the excretion of electrolytes, is influenced by systemic exposure to the drugs. The relatively higher distribution into the kidneys of rofecoxib and celecoxib compared with meloxicam suggests involvement of direct drug exposure in the kidneys in the adverse renal effect.

The effects of paracetamol and parecoxib on kidney function in elderly patients undergoing orthopedic surgery

The common adverse effects of traditional nonsteroidal antiinflammatory drugs on renal function include reductions in renal blood flow, glomerular filtration rate, and sodium and potassium excretion, mainly via inhibition of renal cyclooxygenase. We designed the present study to determine the effects of IV paracetamol or parecoxib on renal function in elderly patients undergoing orthopedic surgery. Seventy-five patients (76 +/- 8 yr, mean +/- sd) undergoing hip replacement or surgery of the femoral shaft completed this randomized and placebo-controlled study. After their arrival in the postanesthesia care unit, patients received an initial dose of the study medication, paracetamol 1000 mg IV (n = 25), parecoxib 40 mg IV (n = 25), or saline IV (n = 25); subsequent doses were administered for the next 3 days. Opioids were provided as rescue medication. Blood and urine samples were collected before and after surgery, and markers of renal function were determined. During the first 2 h after the initial dose of parecoxib, creatinine clearance was slightly diminished (125 +/- 83 to 86 +/- 45 mL/min, P < 0.05), whereas no significant decrease of creatinine clearance was observed in the placebo and paracetamol groups. After all treatments, sodium and potassium excretion as well as urine albumin and alpha-1-microglobulin were transiently increased (group differences: not signicifant). In conclusion, glomerular and tubular functions were transiently affected in all patients after orthopedic surgery; however, the differences between the treatment groups were small and not clinically relevant. Further studies are warranted to determine adverse renal effects of longer-lasting therapy with these drugs, especially in patients with renal impairment or concomitant diseases.

Action of diclofenac on kidney mitochondria and cells

The mitochondrial membrane potential measured in isolated rat kidney mitochondria and in digitonin-permeabilized MDCK type II cells pre-energized with succinate, glutamate, and/or malate was reduced by micromolar diclofenac dose-dependently. However, ATP biosynthesis from glutamate/malate was significantly more compromised compared to that from succinate. Inhibition of the malate-aspartate shuttle by diclofenac with a resultant decrease in the ability of mitochondria to generate NAD(P)H was demonstrated. Diclofenac however had no effect on the activities of NADH dehydrogenase, glutamate dehydrogenase, and malate dehydrogenase. In conclusion, decreased NAD(P)H production due to an inhibition of the entry of malate and glutamate via the malate-aspartate shuttle explained the more pronounced decreased rate of ATP biosynthesis from glutamate and malate by diclofenac. This drug, therefore affects the bioavailability of two major respiratory complex I substrates which would normally contribute substantially to supplying the reducing equivalents for mitochondrial electron transport for generation of ATP in the renal cell.

Removing the threat of diclofenac to critically endangered Asian vultures

Veterinary use of the nonsteroidal anti-inflammatory (NSAID) drug diclofenac in South Asia has resulted in the collapse of populations of three vulture species of the genus Gyps to the most severe category of global extinction risk. Vultures are exposed to diclofenac when scavenging on livestock treated with the drug shortly before death. Diclofenac causes kidney damage, increased serum uric acid concentrations, visceral gout, and death. Concern about this issue led the Indian Government to announce its intention to ban the veterinary use of diclofenac by September 2005. Implementation of a ban is still in progress late in 2005, and to facilitate this we sought potential alternative NSAIDs by obtaining information from captive bird collections worldwide. We found that the NSAID meloxicam had been administered to 35 captive Gyps vultures with no apparent ill effects. We then undertook a phased programme of safety testing of meloxicam on the African white-backed vulture Gyps africanus, which we had previously established to be as susceptible to diclofenac poisoning as the endangered Asian Gyps vultures. We estimated the likely maximum level of exposure (MLE) of wild vultures and dosed birds by gavage (oral administration) with increasing quantities of the drug until the likely MLE was exceeded in a sample of 40 G. africanus. Subsequently, six G. africanus were fed tissues from cattle which had been treated with a higher than standard veterinary course of meloxicam prior to death. In the final phase, ten Asian vultures of two of the endangered species (Gyps bengalensis, Gyps indicus) were dosed with meloxicam by gavage; five of them at more than the likely MLE dosage. All meloxicam-treated birds survived all treatments, and none suffered any obvious clinical effects. Serum uric acid concentrations remained within the normal limits throughout, and were significantly lower than those from birds treated with diclofenac in other studies. We conclude that meloxicam is of low toxicity to Gyps vultures and that its use in place of diclofenac would reduce vulture mortality substantially in the Indian subcontinent. Meloxicam is already available for veterinary use in India.

Resection and use of a cyclooxygenase-2 inhibitor for treatment of pancreatic adenocarcinoma in a cockatiel

CASE DESCRIPTION

A 5-year-old sexually intact male cockatiel was examined because of progressive dyspnea of 1 week's duration.

CLINICAL FINDINGS

On auscultation of the lungs and air sacs, crackles were detected; the abdomen was distended and fluctuant on palpation. Eleven milliliters of clear yellow fluid was collected via abdominocentesis. Radiography (with and without contrast medium) and ultrasonography revealed a soft tissue mass in the caudoventral portion of the coelom.

TREATMENT AND OUTCOME

Exploratory surgery of the coelomic cavity was performed and the neoplasm was excised. Histologic examination of the neoplasm was consistent with a high-grade pancreatic exocrine adenocarcinoma. Celecoxib, a cyclooxygenase (COX)-2 inhibitor, was administered for pain management and for potential antineoplastic activity. For 4.5 months after surgery, the bird had no recurrence of clinical signs; however, dyspnea recurred and during evaluation, the bird died. Necropsy findings indicated that the pancreatic adenocarcinoma had metastasized to surrounding tissues and vessels, which was not unexpected given the high grade assigned to the neoplasm during histologic analysis.

CLINICAL RELEVANCE

Pancreatic neoplasms are associated with a poor prognosis, regardless of treatment modality. Celecoxib can be administered as palliative treatment to affected birds, but as with any nonsteroidal anti-inflammatory drug, COX-2 inhibitors should be used cautiously because they can adversely affect renal function by decreasing renal prostaglandin synthesis.

Analgesics and Osteoarthritis: Are Treatment Guidelines Reflected in Clinical Practice?

Osteoarthritis (OA) treatment is complex and multifactorial, with pharmacological regimens requiring sufficient flexibility to be adapted to individual disease progression, flare ups, and response to treatment. Coexisting conditions are common and can lead to problems regarding polypharmacy. Several guidelines have been published for the management of OA pain. While differences exist, most recommend paracetamol as the initial oral drug for OA, based on its efficacy, tolerability, and cost; in patients who respond inadequately to paracetamol, supplementary or replacement analgesics should be recommended. This article considers the reality of analgesic use for OA in clinical practice and the extent to which guidelines are followed both in primary and secondary care. An international survey of rheumatologists (n = 610) found that paracetamol was recommended as first-choice analgesic for OA by 82% of those surveyed. Similarly, in a survey of French GPs, 90% of those surveyed recommended paracetamol first line; NSAIDs were recommended more frequently for stronger pain relief but were also recommended alongside paracetamol as a first-line treatment of mild to moderate pain by 43% of GPs. Finally, a UK patient survey, conducted at a London hospital (n = 200), found that 64% of patients were taking more than 1 drug for treatment of painful OA of the knee or hip; 76% were taking paracetamol and 40% were taking an NSAID. A further 39% had used an NSAID in the past but switched treatment, primarily due to side effects. These findings reinforce the case for the simple analgesic paracetamol to be seen as the cornerstone of pharmacological OA treatment, both as a first-line analgesic and as a foundation to which additional treatment modalities, including NSAIDs, can be added if and when necessary.

Nonsteroidal Anti-inflammatory Drug Use in the Prevention and Treatment of Squamous Cell Carcinoma

BACKGROUND

Nonsteroidal anti-inflammatory drugs are widely reported to inhibit carcinogenesis.

OBJECTIVE

The objective was to review the literature on nonsteroidal anti-inflammatory drugs in the prevention and treatment of cancer as it pertains to cutaneous squamous cell carcinoma.

METHODS

We searched MEDLINE and performed a review of all published data on nonsteroidal anti-inflammatory drugs and cutaneous oncogenesis.

RESULTS

In vitro and animal data strongly suggest a role for cyclooxygenase-2 in the formation of actinic keratoses and squamous cell carcinomas. Further observational studies and clinical trials are needed to assess their putative role in chemoprevention.

CONCLUSIONS

Nonsteroidal anti-inflammatory drugs have activity against squamous cell carcinomas in vitro and in animal models, as well as in precursor lesions of squamous cell carcinomas. Human trials using selective cyclooxygenase-2 inhibitors are currently in progress and should offer exciting information regarding the chemopreventative function of nonsteroidal anti-inflammatory drugs.

Interspecies Differences in the Nephrotoxic Response to Cyclooxygenase Inhibition

In contrast to cyclooxygenase-1 (COX-1), the basal expression of renal cyclooxygenase-2 (COX-2) varies among species. High basal levels of COX-2 in the renal cortex and papilla in dogs compared with monkeys suggest that COX-2 inhibition may lead to distinct nephrotoxic responses. In this study, we compared the renal effects of COX inhibition between dogs and cynomolgus monkeys (n = 6/group) following the administration of naproxen sodium, a non-selective COX-1/COX-2 inhibitor. Dogs and monkeys were treated with 50 or 150 mg/kg/day naproxen sodium, respectively, for 2 to 6 weeks. Naproxen doses used in this study resulted in equivalent inhibition of COX activity in both species as measured by reductions in urinary prostaglandin E2 (PGE2) and 6-keto-PGF1-alpha levels. There was prominent reduction in renal blood flow (43%) and urinary sodium excretion (62%) in dogs but no alterations in renal blood flow and only minimal change (19%) in urinary sodium excretion in monkeys. The canine but not monkey kidney showed prominent COX-2 expression in the macula densa, thick ascending limb of Henle and papillary interstitial cells by immunohistochemistry. After treatment, the canine but not monkey kidneys had mild to moderate renal tubular atrophy and interstitial fibrosis and renal papillary necrosis. Obstructive nephropathy secondary to intra-tubular drug accumulation was seen in monkeys but not in dogs. Collectively, these data demonstrate species differences in the renal response to COX inhibition. The nature of functional and morphologic changes suggests a more prominent role of COX-2 in renal hemodynamics and natriuresis in dogs than in monkeys.

Prostaglandin endoperoxide H synthase inhibitors and other tocolytics in preterm labour

Preterm delivery (<37 weeks of gestation) is the major obstetrical complication in developed countries, yet attempts to delay labour and prolong pregnancy have largely been unsuccessful. One of the many reasons it is so difficult to prevent preterm birth is that the nature of preterm labour changes as a function of gestational age, maternal lifestyle factors or infection, to list a few of the reasons. The inhibitors of prostaglandin endoperoxide H synthase (PGHS), known as the Non-steroidal Antiinflammatory Drugs, have been viewed with interest as tocolytics with promising effectiveness under most conditions of preterm labour. Three isoforms of PGHS exist; the first two, PGHS-1 and -2, have been studied for their catalytic activity, X-ray crystallographic structure, and physiological roles in the adult and the foetus. Mixed inhibitors and isoform-specific inhibitors of PGHS have been developed, and their roles in delaying preterm labour are examined and compared to other tocolytics.

Rofecoxib: an update on physicochemical, pharmaceutical, pharmacodynamic and pharmacokinetic aspects

Rofecoxib (MK-966) is a new generation non-steroidal anti-inflammatory agent (NSAID) that exhibits promising anti-inflammatory, analgesic and antipyretic activity. It selectively inhibits cyclooxygenase (COX)-2 isoenzyme in a dose-dependent manner in man. No significant inhibition of COX-1 is observed with rofecoxib up to doses of 1000 mg. The pharmacokinetics of rofecoxib has been found to be complex and variable. Mean oral bioavailability after single dose of rofecoxib (12.5, 25 or 50 mg) is 93% with t(max) varying widely between 2 and 9 h. It is highly plasma-protein bound and is metabolized primarily by cytosolic reductases to inactive metabolites. Rofecoxib is eliminated predominantly by hepatic metabolism with a terminal half-life of approximately 17 h during steady state. Various experimental models and clinical studies have demonstrated rofecoxib to be superior, or at least equivalent, in anti-inflammatory, analgesic and antipyretic efficacy to comparator nonselective NSAIDs in osteoarthritis, rheumatoid arthritis and other pain models. Emerging evidence suggests that rofecoxib may also find potential use as supportive therapy in various pathophysiologic conditions like Alzheimer's disease, and in various malignant tumours and polyps, where COX-2 is overly expressed. Rofecoxib is generally well-tolerated. Analysis of data pooled from several trials suggests that rofecoxib is associated with fewer incidences of clinically symptomatic gastrointestinal ulcers and ulcer complications vis-à-vis conventional NSAIDs. However, this gastropreserving effect may be negated by concurrent use of low-dose aspirin for cardiovascular risk reduction. Rofecoxib tends to show similar tolerability for renal and cardiothrombotic events as compared with nonnaproxen nonselective NSAIDs. No clinically significant drug interaction has been reported for rofecoxib except with diuretics, where it reverses their salt-wasting effect and thus can be clinically exploited in electrolyte-wasting disorders. There is only modest information about the physicochemical and pharmaceutical aspects of rofecoxib. Being poorly water soluble, its drug delivery has been improved using varied formulation approaches. Although it is stable in solid state, rofecoxib is photosensitive and base-sensitive in solution form with its degradation mechanistics elucidated. Analytical determinations of rofecoxib and its metabolites in biological fluids employing HPLC with varied types of detectors have been reported. Isolated studies have also been published on the chromatographic and spectrophotometric assay of rofecoxib and its degradants in bulk samples and pharmaceutical dosage forms. The current article provides an updated overview on the physicochemical, pharmaceutical, pharmacokinetic and pharmacodynamic vistas of rofecoxib.

Inhibition of COX-2 prevents hypertension and proteinuria associated with a decrease of 8-iso-PGF2alpha formation in L-NAME-treated rats

BACKGROUND

The inhibition of nitric oxide (NO) exerts injurious effects on the cardiovascular system by several mechanisms, such as the activation of the renin-angiotensin system, oxidative stress, and inflammatory cytokines. We examined whether COX-2, an inducible isoform of cyclooxygenase, is associated with the pathogenesis observed in N(omega)-nitro-L-arginine methyl ester (L-NAME)-induced hypertensive rats.

METHODS

Three groups of 8-week-old male Sprague-Dawley rats were studied (n = 6 in each group): group 1, untreated controls; group 2, treated with L-NAME (1 g/l for 3 weeks, p.o.); and group 3, L-NAME co-treated with COX-2 inhibitor NS-398 (5 mg/kg per day, i.p.). The L-NAME-induced expression of COX-2 mRNA and protein was semi-quantified in the kidneys and the thoracic aorta. Urinary excretion of the prostaglandin 6-keto PGF(1alpha), thromboxane B2 (TXB2), and prostaglandin E2 (PGE2) was measured in the three groups. Moreover, urinary excretion of 8-iso-PGF(2alpha), a potent vasoconstricting arachidonic acid metabolite acting through thromboxane A (TXA) receptor activation, proposed recently as a marker of oxidative stress, was also measured.

RESULTS

L-NAME induced significant increases in systolic blood pressure (P< 0.01), urinary protein (P< 0.05), and renal excretion of 8-iso-PGF(2alpha)(P< 0.01), compared with the control. In L-NAME-treated rats, the levels of COX-2 mRNA and protein were more than 50% higher in the kidneys (P< 0.05), and six-fold higher in the thoracic aorta (P< 0.01) than in control rats. NS-398 significantly ameliorated an increase in systolic blood pressure (P< 0.01) and urinary protein (P< 0.05) induced by L-NAME.

CONCLUSIONS

These data indicate that an increase in COX-2 expression might have a hypertensive effect, partly associated with 8-iso-PGF(2alpha) formation in l-NAME-treated rats.