Nephrotoxicity of nonsteroidal anti-inflammatory drugs: physiologic foundations and clinical implications

Adverse renal effects of anti-inflammatory agents: evaluation of selective and nonselective cyclooxygenase inhibitors

Conventional nonsteroidal anti-inflammatory drugs (NSAIDs), i.e. nonselective cyclooxygenase COX inhibitors have well-documented nephrotoxicity. Adverse renal effects occur because of inhibition of the synthesis of cyclooxygenase-derived prostaglandins which act to modulate pathologic processes that would normally impair various renal functions. The introduction of the selective COX-2 inhibitors raised hope that this class of drugs would reduce injury in both the gastrointestinal tract and the kidneys. Animal and human data, however, suggest that COX-2 synthesized prostaglandins are important in the modulation of renal physiology during adverse conditions. Hence, it appears that these drugs are equal in causing nephrotoxicity as the nonselective COX inhibitors.

Treatment of heart failure in older persons. Dilemmas with coexisting conditions: diabetes mellitus, chronic obstructive pulmonary disease, and arthritis

Diabetes mellitus is a risk factor for congestive heart failure. Diabetics with congestive heart failure should have good glycemic control, treatment of hypertension and dyslipidemia, and treatment with diuretics, angiotensin-converting enzyme inhibitors, and beta blockers as well as digoxin, if the left ventricular ejection fraction is abnormal. Patients with chronic obstructive pulmonary disease may have left ventricular failure because of a coexistent cardiac disorder or right ventricular failure from pulmonary hypertension. An acute respiratory tract infection may precipitate right ventricular failure and should be treated. Alveolar hypoxia should be corrected by improving alveolar ventilation through relieving airflow obstruction with bronchodilators and by increasing inspired oxygen concentration. Loop diuretics should be used cautiously. Beta blockers may be given to patients with chronic obstructive pulmonary disease and left ventricular failure if bronchospasm is not present. Angiotensin-converting enzyme inhibitors should be used to treat left ventricular failure. Digitalis should not be used in patients with right ventricular failure due to chronic obstructive pulmonary disease. Nonsteroidal anti-inflammatory drugs are contraindicated in patients with congestive heart failure. There are controversial data about the negative interaction between aspirin and angiotensin-converting enzyme inhibitors in patients with congestive heart failure. Patients with arthritis and congestive heart failure needing large doses of aspirin for pain relief may be treated instead with acetaminophen, tramadol, or Percocet if necessary for chronic severe pain.

Cyclooxygenase-2 inhibitors: is there an association with coronary or renal events?

The article is concerned with the effects of specific cyclooxygenase-2 (COX-2) inhibitors and their relationship to thrombotic cardiovascular events and to renal disease. Clinical and experimental aspects of COX-2-specific inhibitors are cited. A COX-2 inhibitor, celecoxib, interferes with myocardial prostacyclin production and also produces hypertension. Data have shown that in animal experiments, celecoxib also lowers myocardial prostaglandin concentration but fails to inhibit thromboxane concentration to the same degree. In the kidney, celecoxib can result in glomerular and interstitial nephritis or papillary necrosis. As in infarcted heart muscle, the COX-2-specific inhibitor celecoxib causes a significant decline in prostaglandin in the renal medulla. It was concluded from both clinical and experimental findings that COX-2 inhibitors can cause thrombotic cardiovascular events as well as renal disease. For these reasons, care should be exercised in administering specific COX-2 inhibitors to patients with pre-existing cardiac or renal disease.

Opioid and non-opioid analgesics

Opioids are the most potent analgesics. Toxicity results either from effects mediated by variation in affinity and intrinsic efficacy at specific opioid receptors or, rarely, from a direct toxic effect of the drugs. For some adverse effects, opioids exhibit a 'dual pharmacology' whereby these effects are usually observed only in pain-free individuals, and are not seen in patients in pain. Paracetamol, although generally very safe in therapeutic doses, displays potentially fatal toxicity in overdose requiring specific treatment. Non-steroidal anti-inflammatory drugs (NSAIDs) are known to act by inhibiting COX-1 and COX-2 isoenzymes to various degrees. Toxicity arises primarily from undesired inhibition at these enzyme sites. Knowledge of the mechanism of action of these drugs is fundamental to the understanding of their potential for toxicity, the details of which are still emerging.

Nonsteroidal antiinflammatory drugs as a trigger of clinical heart failure

BACKGROUND

Two recent studies estimated that users of nonsteroidal antiinflammatory drugs (NSAIDs) have a two-fold increase in risk of hospitalization for congestive heart failure and that this effect is larger among patients with preexisting cardiovascular diseases.

METHODS

To evaluate the association between NSAID use and the risk of first-diagnosed episode of heart failure, we conducted a case-control study nested in a population-based cohort of individuals 40-84 years of age and registered in the U.K. General Practice Research Database at 1 January 1996. We excluded patients with a diagnosis of heart failure or cancer before that time and followed source members until a first-time recorded diagnosis of heart failure or cancer, or until 31 December 1996 if no disease occurred. The analysis included 857 confirmed cases and 5000 controls frequency-matched to cases by age (interval of 1 year) and sex.

RESULTS

The estimated adjusted relative risk of heart failure associated with prescription of NSAIDs was 1.6 (95% confidence interval = 1.2-2.1). The relative risk was greater during the first month of therapy and was independent of treatment indication. The relative risk was 1.9 (1.3-2.8) among patients with prior history of hypertension, diabetes or renal failure and 1.3 (0.9-1.9) among individuals without these conditions.

CONCLUSIONS

Initiation of NSAID therapy may double the risk of developing heart failure in susceptible individuals. Patients with renal failure, diabetes or hypertension when taking NSAIDs might be at a greater risk of developing heart failure than patients without those conditions.

The therapeutic potential of NO-NSAIDs

NSAIDs, including those that are selective for cyclooxygenase-2, are among the most widely used drugs. However, these drugs produce significant side effects in the gastrointestinal and cardiorenal systems, which greatly limit their utility. In recent years, a new type of anti-inflammatory agent has been developed that appears to offer significant advantages over conventional and Cox-2-selective NSAIDs. No-NSAIDs are derivatives of conventional NSAIDs, which are able to release nitric oxide over prolonged periods of time. The combination of balanced inhibition of the two main isoforms of COX with controlled release of nitric oxide yields a series of drugs that exert anti-inflammatory and analgesic activities in a wide range of settings, and have markedly reduced gastrointestinal and cardiorenal toxicity. Recent clinical trials of NO-NSAIDs have provided a 'proof of concept' that is completely consistent with pre-clinical characterization of these compounds.

A model analysis of costs of blood pressure destabilization and edema associated with rofecoxib and celecoxib among older patients with osteoarthritis and hypertension in a Medicare Choice population

BACKGROUND

Economic analyses consider all costs relevant to the use of a particular treatment or treatments. Recently, head-to-head, randomized, controlled trials have shown a significantly higher incidence of blood pressure (BP) destabilization and clinically significant edema with rofecoxib than with celecoxib among older, hypertensive patients with osteoarthritis (OA).

OBJECTIVE

The objective of this analysis was to estimate the COX-2 specific inhibitor medication costs, in addition to the costs of drugs and physicians' fees, for BP destabilization and clinically significant edema associated with the use of rofecoxib 25 mg QD and celecoxib 200 mg QD in patients with OA and hypertension in a Medicare Choice population (aged > or = 65 years).

METHODS

A decision analysis model was constructed to determine the costs (from the payer's perspective) of treating patients in this population with either of the 2 regimens for 6 weeks. The analysis used pooled data from 2 recent, independently conducted, multicenter, double-blind, randomized, controlled trials of OA patients aged > or = 65 years with treated hypertension who received either celecoxib 200 mg QD or rofecoxib 25 mg QD for 6 weeks. In the individual trials, rofecoxib was associated with significantly higher rates of destabilized BP (P < 0.032 and P < 0.001) and edema (P < 0.01 and P = 0.045) than celecoxib.

RESULTS

For a 100,000-member Medicare Choice population, an estimated 25,630 persons would have OA and hypertension (stages I-III), and an estimated 5126 of these patients would use celecoxib or rofecoxib. The estimated costs were 33,938 dollars (6.2%) higher if all hypertensive patients with OA were treated with rofecoxib rather than celecoxib for 6 weeks. The cost per day of use was 0.16 dollars less with celecoxib, and per-patient, per-month costs were 4.79 dollars lower.

CONCLUSION

Celecoxib was a less costly treatment option than rofecoxib among OA patients with hypertension aged > or = 65 years, based on our model of the direct costs of COX-2 specific inhibitor therapy combined with those associated with physician monitoring and treatment of edema and BP destabilization.

Does cyclooxygenase-2 affect blood pressure?

With the development and clinical implementation of the new cyclooxygenase (COX)-2 inhibitors, their safety, including the effects on renal function and blood pressure, is attracting increasing attention. In the kidney, COX-2 is constitutively expressed and is highly regulated in response to alterations in intravascular volume. COX-2 metabolites have been implicated in mediation of renin release, regulation of sodium excretion, and maintenance of renal blood flow. Similar to conventional nonsteroidal anti-inflammatory drugs, inhibition of COX-2 may cause modest elevations in blood pressure in a minority of subjects. COX-2 inhibitors may also exacerbate pre-existing hypertension or interfere with other antihypertensive drugs. Special caution should be taken in patients with volume depletion or decreased organ perfusion.

The adverse renal effects of prostaglandin-synthesis inhibitors in the newborn rabbit

Nonsteroidal anti-inflammatory drugs are frequently used during pregnancy (premature labor, polyhydramnios) and the immediate postnatal period (closure of patent ductus arteriosus). This article evaluates the renal effect of 3 nonspecific COX inhibitors (aspirin, indomethacin, and ibuprofen) in newborn rabbits. Five groups of anesthetized, ventilated, normoxemic 6-day-old rabbits (n = 52) were administered intravenous aspirin (40 mg/kg), indomethacin (2 mg/kg), and ibuprofen (0.02, 0.2, 2.0 mg/kg, respectively). Renal function and hemodynamics as assessed by inulin and para-aminohippuric acid clearances were measured before and in the hour after drug administration. In all groups of animals, the nonselective COX inhibitors induced an increase in renal vascular resistance and a consequent decrease in glomerular filtration rate and renal blood flow. Urine flow rate decreased significantly in all groups, except in the group receiving the lowest dose of ibuprofen. In newborn rabbits, aspirin, indomethacin, and ibuprofen induced intense renal vasoconstriction, which resulted in impaired renal function. This observation illustrates the major renal protective role played by the vasodilatory prostaglandins during the neonatal period, when the kidney is perfused at very low perfusion pressure. We conclude that all COX inhibitors should be administered with the same caution to the preterm neonate.

Nephrotic syndrome and interstitial nephritis associated with celecoxib

Nonsteroidal anti-inflammatory drugs (NSAIDs) are well known to cause fluid and electrolyte abnormalities and renal failure. NSAIDs also may cause an acute allergic interstitial nephritis (AIN) and the nephrotic syndrome, characterized by histologic pathology consistent with minimal change disease in patients with previously normal renal function. The nephrotoxic potential of cyclooxygenase 2 (COX-2) inhibitors has not been established because AIN associated with nephrotic syndrome has not been reported secondary to the COX-2 inhibitors. This case report describes the first case of AIN associated with nephrotic syndrome in a patient treated with the selective COX-2 inhibitor, celecoxib.

The Renal Effects of Traditional Nonsteroidal Anti-Inflammatory Agents Versus Cyclooxygenase-2 Inhibitors

Nonsteroidal anti-inflammatory drugs (NSAIDs) are commonly used for the management of acute and chronic pain as well as for rheumatoid arthritis and osteoarthritis. Although gastrointestinal complications are the most common adverse events associated with the use of these drugs, the renal adverse effects such as acute renal failure, electrolyte abnormalities, nephrotic syndrome, interstitial nephritis, and papillary necrosis can be serious. The cyclooxygenase-2 (COX-2)- selective NSAIDs (celecoxib, rofecoxib) have been associated with a reduced frequency of gastrointestinal adverse events, but questions still remain as to their renal safety. Recent information has suggested an increased role for COX-2 as a constitutive renal enzyme, thus implying its importance for normal kidney homeostasis. Clinical studies and published case reports of renal adverse events associated with COX-2 inhibitors suggest that patients with decreased effective circulating blood volume, salt depletion, and renal insufficiency have an increased likelihood of renal-related adverse events. Because many older patients have conditions that place them in one of the “at-risk” categories, this population should be monitored closely for the development of renal adverse events from any NSAIDs, including COX-2-selective agents.

Incidence of gastroduodenal ulcers associated with valdecoxib compared with that of ibuprofen and diclofenac in patients with osteoarthritis

OBJECTIVE

To determine whether valdecoxib, at chronic arthritis doses, has the characteristics of a cyclo-oxygenase 2 (COX-2) specific inhibitor, as measured by a reduced incidence of upper-gastrointestinal ulceration compared with conventional nonsteroidal anti-inflammatory drugs (NSAIDs).

METHODS

This double-blind, multicentre, placebo-controlled, parallel-group study compared the incidence of gastroduodenal ulcers associated with valdecoxib 10 mg daily (q.d.) and 20 mg q.d. with that of ibuprofen 800 mg three times daily (t.i.d.) or diclofenac 75 mg twice daily (b.i.d.) when administered over a 12-week period. The incidence of gastroduodenal ulcers was assessed by upper-gastrointestinal endoscopy, performed at baseline and again at the end of week 12 (or at early study termination). Efficacy assessments were performed at baseline and at weeks 2, 6 and 12 using Patient's and Physician's Global Assessments of Arthritis.

RESULTS

A total of 1052 osteoarthritis patients were enrolled into the trial. The incidence of gastroduodenal ulcers over 12 weeks was 5% in patients receiving valdecoxib 10 mg q.d., 4% in patients receiving valdecoxib 20 mg q.d., 7% in patients receiving placebo, 16% in patients receiving ibuprofen 800 mg t.i.d. (P <0.05 v. placebo), and 17% in patients receiving diclofenac 75 mg b.i.d. (P <0.05 v. placebo). The incidence of gastroduodenal ulcers at week 12 seen in the ibuprofen 800 mg t.i.d. and diclofenac 75 mg b.i.d. groups was significantly higher than that in the valdecoxib 10 mg q.d. and valdecoxib 20 mg q.d. groups (P <0.05). The incidence rates of gastroduodenal ulcers were not significantly different between the valdecoxib treatment groups or between valdecoxib- and placebo-treated patients. Efficacy responses to valdecoxib 10 mg and 20 mg q.d. were significantly greater than placebo and comparable with both ibuprofen 800 mg t.i.d. and diclofenac 75 mg b.i.d.

CONCLUSIONS

The results of the study demonstrate that valdecoxib has an upper-gastrointestinal safety profile typical of a COX-2 specific inhibitor. Overall, the data indicate that administration of valdecoxib offers similar efficacy for the treatment of osteoarthritis but improved upper-gastrointestinal safety compared with the conventional NSAIDs, ibuprofen and diclofenac, based on the significantly lower incidence of gastroduodenal ulcers detected by endoscopy.

The involvement of nervous and some inflammatory response mechanisms in the acute snuff-induced gingival hyperaemia in humans

BACKGROUND AND AIM

Tobacco users and especially cigarette smokers are at higher risk than non-smokers for periodontal disease. The pathogenic mechanism has been proposed to be the vasoconstrictive properties of nicotine, with reduced gingival blood flow (GBF) as a contributing factor in the development of periodontal disease. However, in a previous study in humans, we found GBF to increase in response to acute exposure to snuff. The present study was designed to investigate whether the tobacco-induced acute GBF increase is dependent on intact nervous conduction. We further investigated the effect of piroxicam (NSAID) and dexchlorpheniramin (DCPA) (antihistamine) on the snuff-induced responses in the gingiva, to see if chemical mediators of inflammation also influenced the response.

MATERIAL AND METHODS

Laser Doppler flowmetry (LDF) was used to measure gingival blood flow bilaterally in the buccal maxillary gingiva, in the forehead skin and in the thumb. Also arterial blood pressure (BP) and heart rate (HR) were monitored. Infraorbital nerve block anaesthesia (INB), superficial mucosal anaesthesia, 20 mg piroxicam or 2 mg DCPA were used in combination with snuff to study the vascular responses to 500 mg snuff (1% nicotine).

RESULTS

Snuff induced a rapid increase in GBF that was higher than the increase in BP, indicating an active vasodilatation. The snuff-induced vasodilatation was partly blocked by INB and more so by superficial mucosal anaesthesia. Piroxicam and DCPA exerted diverse effects on vascular homeostasis but had no effect on the snuff-induced vasodilatation in the gingiva.

CONCLUSIONS

The results of this study confirm that snuff induces local gingival vasodilatation, and imply that this vasodilatation most likely is a summation of responses due to both autonomic and antidromic reflex mechanisms. We further discuss the possible involvement of the nervously mediated effects of tobacco and nicotine on vascular homeostasis and in tobacco-associated periodontitis.

Effect of misoprostol on ibuprofen-induced renal dysfunction in patients with decompensated cirrhosis: results of a double-blind placebo-controlled parallel group study

OBJECTIVES

Patients with cirrhosis are prone to develop renal failure upon administration of nonsteroidal anti-inflammatory drugs. The aim of the present study was to determine the safety and efficacy of misoprostol (400 microg) in two repeated doses for the prevention of ibuprofen-induced decrements in renal function in decompensated cirrhotics.

METHODS

Patients were given ibuprofen (800 mg) with either misoprostol (n = 9) or a placebo (n = 10). Sixty minutes later another dose of misoprostol or the placebo was administered. Renal function tests were assessed by clearance techniques.

RESULTS

Administration of ibuprofen with a placebo caused significant decreases in urinary output, inulin clearance, sodium excretion, osmolar clearance, free water clearance, and urinary prostaglandin E2 excretion. Coadministration of ibuprofen and the first misoprostol dose maintained urinary output and sodium excretion, and caused an increase in free water clearance. These changes were maintained only for 1 h. Administration of the second dose of misoprostol temporarily improved inulin and creatinine clearances. Half the patients who received misoprostol suffered from episodes of chills, fever, and diarrhea.

CONCLUSION

Ibuprofen causes renal dysfunction in decompensated cirrhotics, whereas misoprostol may have some protective renal effects, which are, however, short lived and clinically insignificant. Because of side effects, misoprostol should be used with caution in these patients.

Rheumatoid arthritis: developing pharmacological therapies

Rheumatoid arthritis (RA) is a chronic inflammatory disease that, despite recent advances in therapy, still results in significant morbidity, mortality and disability. The aetiology remains unknown and past therapies, although helpful for the majority of patients, have been suboptimal. The recent introduction of newer agents has changed the treatment paradigm of RA. COX-2 inhibitors, anti-TNF agents and interleukin-1 antagonists have allowed us to treat RA more effectively with relatively low risk of side effects. Investigations of other possible treatment pathways, such as inhibition of angiogenesis, may produce still better treatment and rapid unraveling of the immune system and how it relates to RA greatly enhances the opportunities for improved therapeutics in RA.

High blood pressure in the geriatric population: treatment considerations

Increases in blood pressure (BP), particularly systolic BP, have traditionally been considered to be a normal or "physiologic" component of the aging process. However, it is now clear that elevated BP, particularly systolic BP, represents a pathophysiologic manifestation of altered cardiovascular physiology and structure, ultimately manifesting as increased cardiovascular morbidity and mortality (myocardial infarction, stroke, and total cardiovascular death rates). More than one half of the population aged 65 or older have hypertension, defined as BP > or = 140/90 mm Hg. Framingham data indicate that the risk of coronary heart disease increases with lower diastolic BP at any level of systolic BP > or = 120 mm Hg, thus further stressing the importance of pressure-induced arterial vascular compliance changes and introducing pulse pressure as an important predictor of cardiovascular risk. Geriatric hypertension is generally of a salt-sensitive nature and often associated with impaired baroreflex function. Reduction in sodium intake is important and effective in older patients, and should be initiated before or together with drug therapy. Encouraging data from clinical trials now strongly support the aggressive anti-hypertensive treatment of elderly patients. A recent meta-analysis of eight outcome trials evaluating the risks of treated and untreated isolated systolic hypertension has demonstrated a 30% reduction in combined fatal and nonfatal stroke, a 26% reduction in fatal and nonfatal cardiovascular events, and a 13% reduction in total mortality. Those drugs effective in younger patients also appear effective in the elderly; low-dose thiazides (alone or in combination with potassium sparing agents), beta blockers, long-acting dihydropyridine calcium antagonists, angiotensin-converting enzyme inhibitors, and angiotensin receptor blockers all have demonstrated efficacy. In selecting an agent, it is important to consider comorbid disease states, and to recognize the potential of all nonsteroidal anti-inflammatory drugs, whether conventional or cyclooxygenase-2 specific, to increase BP or interfere with other antihypertensive agents. In general, the elderly should be treated to target BP levels identical to those suggested for younger patients, although a more gradual reduction to target, perhaps with an intermediate BP goal of < 160 mm Hg, may be advisable.

Physician-reported management of edema and destabilized blood pressure in cyclooxygenase-2-specific inhibitor users with osteoarthritis and treated hypertension

BACKGROUND

The addition of a nonsteroidal anti-inflammatory drug to the regimen of a patient with treated hypertension can cause a destabilization of blood pressure.

OBJECTIVE

The aim of this study was to describe physician-reported management of clinically significant edema and/or destabilized blood pressure in patients with osteoarthritis (OA) and hypertension when initiating therapy with rofecoxib or celecoxib.

METHODS

A cross-sectional survey was administered to physicians who attended one of several arthritis consultant programs sponsored by Pharmacia Corporation, with attendees selected by local sales representatives. Each program included a clinical presentation by a physician concerning the cardiorenal safety of celecoxib, followed by a consultative presentation and session led by a Pharmacia Clinical Education Manager.

RESULTS

A total of 828 physicians in the following specialties completed the survey: family practice (33.0%), internal medicine (25.0%), orthopedics (15.2%), and rheumatology (11.4%). Responding physicians expected that the majority of patients who experienced edema would contact them (68.4%). They reported that they schedule follow-up visits for blood pressure monitoring 65.6% of the time after initiating a cyclooxygenase-2 (COX-2)-specific inhibitor, with family practitioners and internists most likely to indicate that they would do so and orthopedists least likely. Responding physicians indicated that the presence of edema and destabilized blood pressure generally led to discontinuation of the COX-2-specific inhibitor (58%-82% of the time). Internists and family practitioners were most likely to report that they treat edema by initiating or modifying diuretic therapy (33%-51% of the time). For destabilized blood pressure, an antihypertensive drug was reported to be initiated or modified 40% to 55% of the time by family practitioners and internists, whereas orthopedists indicated that they referred patients to the primary care provider. The COX-2-specific inhibitor prescribed resulted in management differences: physicians indicated that they were more likely to switch from rofecoxib to celecoxib in the event of edema or destabilized blood pressure, whereas they were more likely to adjust the celecoxib dose than the rofecoxib dose. Because the data were captured from convenience samples of physicians attending sponsored meetings, it is possible that respondents provided the answers they thought the sponsor would want. Because this was a cross-sectional survey, reported behavior was not compared with actual behavior.

CONCLUSIONS

A significant percentage of physicians reported that they monitor patients with OA and hypertension for the occurrence of destabilized blood pressure and edema after initiation of a COX-2-specific inhibitor. Physicians indicated that they would nearly always intervene when either event is identified.

Cyclo-oxygenase 2 function is essential for bone fracture healing

Despite the molecular and histological similarities between fetal bone development and fracture healing, inflammation is an early phase of fracture healing that does not occur during development. Cyclo-oxygenase 2 (COX-2) is induced at inflammation sites and produces proinflammatory prostaglandins. To determine if COX-2 functions in fracture healing, rats were treated with COX-2-selective nonsteroidal anti-inflammatory drugs (NSAIDs) to stop COX-2-dependent prostaglandin production. Radiographic, histological, and mechanical testing determined that fracture healing failed in rats treated with COX-2-selective NSAIDs (celecoxib and rofecoxib). Normal fracture healing also failed in mice homozygous for a null mutation in the COX-2 gene. This shows that COX-2 activity is necessary for normal fracture healing and confirms that the effects of COX-2-selective NSAIDs on fracture healing is caused by inhibition of COX-2 activity and not from a drug side effect. Histological observations suggest that COX-2 is required for normal endochondral ossification during fracture healing. Because mice lacking Cox2 form normal skeletons, our observations indicate that fetal bone development and fracture healing are different and that COX-2 function is specifically essential for fracture healing.

Celecoxib-induced acute interstitial nephritis

Data about the nephrotoxicity of selective cyclooxygenase-2 inhibitors are still evolving. Acute interstitial nephritis is a well-described complication of therapy with nonselective nonsteroidal anti-inflammatory drugs. We report a case of biopsy-proven acute interstitial nephritis in a 73-year-old diabetic woman, who had taken celecoxib for more than 1 year before presentation. She presented with clinical findings of subnephrotic proteinuria and acute renal failure that required dialysis. She recovered renal function with cessation of celecoxib therapy after 2 weeks. Other medications were reintroduced safely, without recurrence of renal failure. A kidney biopsy specimen showed acute interstitial nephritis with a prominent eosinophilic infiltrate in the interstitium. This case documents the occurrence of acute interstitial nephritis with celecoxib and emphasizes the need for continued vigilance and care in use of cyclooxygenase-2 inhibitors in high-risk patients.

Continuous low-level heat wrap therapy provides more efficacy than Ibuprofen and acetaminophen for acute low back pain

STUDY DESIGN

A prospective, randomized, single (investigator) blind, comparative efficacy trial was conducted.

OBJECTIVE

To compare the efficacy of continuous low-level heat wrap therapy (40 C, 8 hours/day) with that of ibuprofen (1200 mg/day) and acetaminophen (4000 mg/day) in subjects with acute nonspecific low back pain.

SUMMARY OF BACKGROUND DATA

The efficacy of topical heat methods, as compared with oral analgesic treatment of low back pain, has not been established.

METHODS

Subjects (n = 371) were randomly assigned to heat wrap (n = 113), acetaminophen (n = 113), or ibuprofen (n = 106) for efficacy evaluation, or to oral placebo (n = 20) or unheated back wrap (n = 19) for blinding. Outcome measures included pain relief, muscle stiffness, lateral trunk flexibility, and disability. Efficacy was measured over two treatment days and two follow-up days.

RESULTS

Day 1 pain relief for the heat wrap (mean, 2) was higher than for ibuprofen (mean, 1.51; P = 0.0007) or acetaminophen (mean, 1.32; P = 0.0001). Extended mean pain relief (Days 3 to 4) for the heat wrap (mean, 2.61) also was higher than for ibuprofen (mean, 1.68; P = 0.0001) or acetaminophen (mean, 1.95; P = 0.0009). Lateral trunk flexibility was improved with the heat wrap (mean change, 4.28 cm) during treatment (P </= 0.009 vs acetaminophen [mean change, 2.93 cm], P </= 0.001 vs ibuprofen [mean change, 2.51 cm]). The results were similar on Day 4. Day 1 reduction in muscle stiffness with the heat wrap (mean, 16.3) was greater than with acetaminophen (mean, 10.5; P = 0.001). Disability was reduced with the heat wrap (mean, 4.9), as compared with ibuprofen (mean, 2.7; P = 0.01) and acetaminophen (mean, 2.9; P = 0.0007), on Day 4. None of the adverse events were serious. The highest rate (10.4%) was reported in the ibuprofen group.

CONCLUSION

Continuous low-level heat wrap therapy was superior to both acetaminophen and ibuprofen for treating low back pain.

Potential cardioprotective actions of no-releasing aspirin

The use of low doses of aspirin on a daily basis has increased greatly in the past 20 years, based on observations that it can significantly reduce the risk of heart attacks and strokes. However, aspirin can also cause severe damage to the stomach. A modified version of aspirin that releases nitric oxide has been developed that seems to offer important advantages over its 103-year-old parent--namely, improved protection for the heart without the unwanted effects on the stomach.

Update of ACR guidelines for osteoarthritis: role of the coxibs

The American College of Rheumatology (ACR) recently provided an update to the guidelines published in 1995 on the management of osteoarthritis (OA) of the knee and hip. Members of the Ad Hoc Committee on OA Guidelines followed an evidence-based medicine approach to revise the guidelines by reviewing an extensive literature search of the Cochrane and Medline databases and published abstracts, and discussing evidence with expert rheumatologists. The goal of the guidelines is to provide recommendations to control patients' OA pain, improve function and health-related quality of life, and avoid therapeutic toxicity. As in the original guidelines, nonpharmacologic interventions involving patient education and physical measures are recommended following initial diagnosis of OA. The pharmacologic algorithm was updated to include currently available therapeutic agents. Acetaminophen remains first-line therapy because of its cost, efficacy, and safety profiles. Cyclooxygenase-2-selective inhibitors (coxibs) have been included as an alternative to nonselective nonsteroidal anti-inflammatory drugs (NSAIDs) in patients at risk for upper gastrointestinal adverse events. Tramadol is an available alternative for patients who have a contraindication to coxibs or nonselective NSAIDs or for those who have not responded to previous oral therapy. Intra-articular injections or topical therapy may be used as monotherapy, or as an adjunct to oral analgesia. Surgical treatment of OA remains a last resort for patients who have failed to respond to nonpharmacologic and pharmacologic treatment approaches, and have progressive limitation in their activities of daily living. Several therapies for the prevention or treatment of OA are currently under investigation, including nutritional supplements, such as glucosamine and chondroitin, disease-modifying OA drugs, and devices, such as acupuncture and electromagnetic therapy. It is anticipated that the guidelines for the management of OA will continue to evolve as new therapies become available.

Different effects of tacrolimus and cyclosporine on renal hemodynamics and blood pressure in healthy subjects

BACKGROUND

The side effects of cyclosporine, nephrotoxicity and hypertension, contribute to long-term renal graft failure and cardiovascular morbidity in graft recipients. It is not clear whether tacrolimus is as nephrotoxic and hypertensive as cyclosporine. Data on this subject are not consistent because of differences in dosage and duration of treatment and the presence of comorbidity in the studied patients. A comparison of both drugs with respect to renal hemodynamics and blood pressure has not been performed yet in healthy subjects.

METHODS

We studied blood pressure, glomerular filtration rate, and effective renal plasma flow in eight healthy subjects at baseline and after 2 weeks administration of cyclosporine and tacrolimus, in randomized order. Trough levels of either drug were within the currently recommended therapeutical range of 100-200 ng/ml for cyclosporine and 5-15 ng/ml for tacrolimus.

RESULTS

Tacrolimus did not influence renal hemodynamic parameters, in contrast to cyclosporine. During cyclosporine, glomerular filtration rate decreased from 98+/-9 ml/min/1.732 to 85+/-10 ml/min/1.732 (P<0.05), and ERPF decreased from 597+/-108 ml/min/1.732 to 438+/-84 ml/min/1.732 (P<0.01). Mean arterial blood pressure increased from 93+/-8 mmHg to 108+/-10 mmHg (P<0.05) during cyclosporine and remained unchanged during tacrolimus.

CONCLUSIONS

We conclude that tacrolimus given during 2 weeks in the currently advised dosage has no unfavorable effects on renal hemodynamics and blood pressure in healthy individuals. The use of tacrolimus in organ transplant recipients may in the long-term lead to better renal function and less cardiovascular morbidity than the use of cyclosporine.

Why do cyclo-oxygenase-2 inhibitors cause cardiovascular events?

This report confirms evidence that selective nonsteroidal anti-inflammatory drugs (NSAIDs), such as celecoxib, can lead to thrombotic cardiovascular events. Aspirin, a nonselective COX-1 (cyclo-oxygenase) and COX-2 inhibitor may result in gastric toxicity. For this reason, selective COX-2 inhibitors have been developed to reduce erosion of the gastric mucosa. Both selective and nonselective NSAIDs reduce prostacyclin formation in the infarcted heart; they accomplish this by tipping the balance of prostacyclin/thromboxane in favor of thromboxane, a prothrombotic eicosanoid. The relative increase in thromboxane, coupled with a diminution in prostacyclin in infarcted heart muscle, can lead to the development of thrombotic cardiovascular events. This may be prevented by the addition of a nitric oxide donor to NSAIDs.

Risks and benefits of nonsteroidal anti-inflammatory drugs in children: a comparison with paracetamol

Nonsteroidal anti-inflammatory drugs (NSAIDs) possess antipyretic, analgesic and anti-inflammatory effects. They are frequently used in children and have numerous therapeutic indications, the most common ones being fever, postoperative pain and inflammatory disorders, such as juvenile idiopathic arthritis (JIA) and Kawasaki disease. Their major mechanism of action is through inhibition of prostaglandin biosynthesis by blockade of cyclo-oxygenase (COX). The disposition of most NSAIDs has been mainly studied in infants > or = 2 years of age. Compared with adults, the volume of distribution and clearance of NSAIDs such as diclofenac, ibuprofen (infants aged between 3 months and 2.5 years), ketorolac and nimesulide were increased in children. The elimination half-life was similar in children to that in adults. These pharmacokinetic differences might be clinically significant with the need for higher loading and/or maintenance doses in children. Ibuprofen, acetylsalicylic acid (ASA) and acetaminophen are the most frequently used agents for fever reduction in children. Over the past 20 years, because of the association between ASA use and Reye's syndrome, most of the interest has been directed toward ibuprofen and acetaminophen. In view of its comparable antipyretic efficacy, but superior tolerability profile, acetaminophen, when used appropriately with age-adapted formulations, should remain the first-line therapy in the treatment of childhood fever. At the moment, there is no scientific evidence to recommend simultaneous use of these two antipyretic drugs. Most NSAIDs provide mild to moderate analgesia, with the exception of ketorolac which has a strong analgesic activity. The analgesic efficacy of ketorolac, ketoprofen, diclofenac and ibuprofen in the treatment of postoperative pain has been mainly studied following a single dose, in children of > or = 1 year of age undergoing minor surgeries. In this setting, when used either alone or in adjunct to caudal or epidural anaesthesia, they were associated with an opioid-sparing effect and were well tolerated. With the exception of ketorolac use in children undergoing tonsillectomy, where controversy exists regarding the risk of postoperative haemorrhage, NSAIDs have not been associated with an increased risk of perioperative bleeding. NSAIDs are the first-line therapy in JIA. They appear to be equally effective and tolerated, with the exception of ASA which is associated with more adverse effects. ASA has been used for many years in the treatment of Kawasaki disease and is part of the standard modality of treatment in combination with intravenous gammaglobulins. More recently, lung inflammation associated with cystic fibrosis (CF) has become a new target for NSAIDs. Despite promising preliminary results with ibuprofen, numerous questions need to be answered before this new strategy becomes part of the conventional treatment of patients with CF. In summary, NSAIDs are effective in reducing fever, alleviating pain and reducing inflammation in children, with a good tolerance profile. Pharmacokinetic studies are needed to characterise the disposition of NSAIDs in very young infants in order to use them rationally. To date, no studies have been published on the disposition, tolerability and efficacy of specific COX-2 inhibitors in children. Further clinical experience with these agents in adults is warranted before undergoing trials with specific COX-2 inhibitors in children.

Selective cyclo-oxygenase-2 inhibitors: cardiovascular and gastrointestinal toxicity

The introduction of selective inhibitors of cyclo-oxygenase-2 to the marketplace has been much anticipated for several years. It would appear that these compounds have lived up to the expectations of having reduced gastrointestinal toxicity and, at least for some indications, of efficacy similar to that of conventional non-steroidal anti-inflammatory drugs. However, there is a growing body of evidence suggesting that cyclo-oxygenase-2 plays a very important role in gastrointestinal mucosal defence, particularly in situations in which the mucosa is damaged or inflamed. Moreover, physiological roles for cyclo-oxygenase-2 both in the renal and cardiovascular systems are becoming better recognized. Inhibition of cyclo-oxygenase-2 can lead to peripheral oedema and hypertension, and may promote thrombosis. Indeed, there is recent evidence of increased rates of myocardial infarction in arthritis patients taking a selective cyclo-oxygenase-2 inhibitor. Use of low-dose aspirin concurrently with use of a selective cyclo-oxygenase-2 inhibitor may provide some degree of protection against the potential cardiovascular toxicity of the latter but both laboratory and clinical studies suggest that the concomitant use of these two types of drugs results in gastrointestinal ulceration comparable to what is seen with conventional non-steroidal anti-inflammatory drugs. These recent results suggest that care must be exercised in the use of selective cyclo-oxygenase-2 inhibitors by individuals who are at increased risk of myocardial infarction and stroke, and the use of low-dose aspirin by these patients may place them at increased risk of gastrointestinal complications.

COX-2 inhibitors. Are they nonsteroidal anti-inflammatory drugs with a better safety profile?

In the treatment of arthritis, NSAIDs are some of the most commonly used drugs, although the prescription of such drugs has been questioned due to their inherent risks for gastrointestinal compromise, platelet effects, and the potential for renal toxicity with long-term use. With the availability of celecoxib and rofecoxib, 2 cyclooxygenase (COX-2) inhibitors (or COX-1 sparing agents) as new forms of NSAIDs, these issues have become magnified not only in the context of risk-to-benefit ratios but also interms of pharmacoeconomics because they have been proven to be equally efficacious as the nonselective NSAIDs, with an improved safety profile particularly within the gastrointestinal tract, but at a significantly increased cost.

Dual acting anti-inflammatory drugs: a reappraisal

Rheumatic diseases are the most prevalent causes of disability in western countries, and non-steroidal anti-inflammatory drugs (NSAIDs) are still the most commonly used remedies. However, NSAIDs cause several serious adverse effects, the most important being from gastric injury to gastric ulceration and renal damage. Attempts to develop non-steroidal anti-inflammatory remedies devoid of these shortcomings-especially gastrointestinal toxicity-have followed several strategies. Non-steroidal anti-inflammatory drugs have, therefore, been associated with gastroprotective agents that counteract the damaging effects of prostaglandin synthesis suppression; however, a combination therapy introduces other problems of pharmacokinetics, toxicity, and patient's compliance. More recently, incorporation of a nitric oxide (NO)-generating moiety into the molecule of several NSAIDs was shown to greatly attenuate their ulcerogenic activity; however, several findings suggest a possible involvement of NO in the pathogenesis of arthritis and subsequent tissue destruction. A most promising approach seemed to be the preparation of novel NSAIDs, targeted at the inducible isoform of prostaglandin synthase (COX-2); they appear to be devoid of gastrointestinal toxicity, in that they spare mucosal prostaglandin synthesis. However, a number of recent studies have raised serious questions about the two central tenets that support this approach, namely that the prostaglandins that mediate inflammation and pain are produced solely via COX-2 and that the prostaglandins that are important in gastrointestinal and renal function are produced solely via COX-1. So, a growing body of evidence shows that COX-2 (not only COX-1) also plays a physiological role in several body functions and that, conversely, COX-1 (not only COX-2) may also be induced at sites of inflammation. More recent and puzzling data shows that COX-2 is induced during the resolution of an inflammatory response, and at this point it produces anti-inflammatory (PGD2 and PGF2alpha), but not proinflammatory (PGE2) prostaglandins; inhibition of COX-2 at this point thus results in persistence of the inflammation. Moreover, COX-2 selective NSAIDs have lost the cardiovascular protective effects of non-selective NSAIDs, effects which are mediated through COX-1 inhibition (in addition, COX-2 has a role in sustaining vascular prostacyclin production). The generation of other very important products of the arachidonic acid cascade (besides cyclooxygenase-produced metabolites) is inhibited neither by non-selective nor by COX-2 selective NSAIDs. The products generated by the 5-lipoxygenase pathway (leukotrienes) are particularly important in inflammation; indeed, leukotrienes increase microvascular permeability and are potent chemotactic agents. Moreover, inhibition of 5-lipoxygenase indirectly reduces the expression of TNF-alpha (a cytokine that plays a key role in inflammation). These data and considerations explain the efforts to obtain drugs able to inhibit both 5-lipoxygenase and cyclooxygenases, the so-called dual acting anti-inflammatory drugs. Such compounds retain the activity of classical NSAIDs, while avoiding their main drawbacks, in that curtailed production of gastroprotective prostaglandins is associated with a concurrent curtailed production of the gastro-damaging and bronchoconstrictive leukotrienes. Moreover, thanks to their mechanism of action, dual acting anti-inflammatory drugs could not merely alleviate symptoms of rheumatic diseases, but might also satisfy, at least in part, the criteria of a more definitive treatment. Indeed, leukotrienes are pro-inflammatory, increase microvascular permeability, are potent chemotactic agents and attract eosinophils, neutrophils and monocytes into the synovium.

COX-1 and COX-2 inhibitors

By inhibiting prostaglandin synthesis, non-steroidal anti-inflammatory drugs (NSAIDs) cause mucosal damage, ulceration and ulcer complication throughout the gastrointestinal tract. The recognition that there are two cyclo-oxygenase enzymes, one predominating at sites of inflammation (COX-2) and one constitutively expressed in the gastrointestinal tract (COX-1), has led to the important therapeutic development of COX-2 inhibitors. COX-2 is phylogenetically more primitive that COX-1 and, while very similar, has critical differences, particularly the existence of a small pocket half way down the active enzyme site. A number of drugs achieve selectivity by binding to this pocket, including presumptively rofecoxib and celecoxib. Others, such as meloxicam, may inhibit COX-2 by different mechanisms. Truly selective COX-2 inhibitors have been shown to have no effect on gastric mucosal prostaglandin synthesis, to cause no acute injury, and no chronic ulceration compared to placebo. Rofecoxib has, in a prospective systematic evaluation involving 8076 patients, been shown to reduce clinically significant ulcers, ulcer complications and gastrointestinal bleeding significantly compared to naproxen. Outcomes data for celecoxib have also been published although differences from the combined comparator agents (diclofenac and ibuprofen) did not reach statistical significance. Use of aspirin in the class study has shown that the benefits of COX-2 inhibitors may be reduced by aspirin use. The VIGOR study has raised the possibility that some NSAIDs, particularly naproxen, may protect against vascular disease compared to COX-2 inhibitors (or placebo).

Renal effects of cyclooxygenase-2 selective inhibitors

Recent in-vitro and animal data show that cyclooxygenase-2 has an integral role in the physiology and pathophysiology of the kidney. Cyclooxygenase-2 regulates renin-angiotensin secretion, and thereby glomerular filtration rate and sodium homeostasis. It is also important for protecting against hypertonic stress. As a consequence, it is not surprising that clinical data verify that selective inhibitors of cyclooxygenase-2 affect renal function to a degree similar to that which has previously been documented with nonselective nonsteroidal anti-inflammatory drugs.

Angiotensin II and prostaglandin interactions on systemic and renal effects of L-NAME in humans

For investigation of whether interactions between prostaglandins and angiotensin II modulate renal response to acute nitric oxide synthesis inhibition in humans, seven young volunteers who were kept on a 240-mM Na diet underwent four experiments with 90 min of infusion of 3.0 microg/kg.min(-1) NG-nitro-L-arginine methyl ester (L-NAME), each preceded by a 3-d treatment with placebo (PL), 50 mg of losartan (LOS), 75 to 125 mg of indomethacin (IND), or both drugs. Mean arterial pressure (MAP), GFR, effective renal plasma flow (ERPF), and Na excretion rate (UNaV) were measured at baseline and from 0 to 45 min and 45 to 90 min of L-NAME infusion. After PL, L-NAME reduced GFR by 5% at 45 min (P < 0.05) and by 9% at 90 min (P < 0.001), ERPF by 11 to 17% (P < 0.001), and UNaV by 28 to 45% (P < 0.001). MAP, unchanged at 45 min, rose by 5% (P < 0.001) at 90 min. LOS prevented pressor but not renal effects of L-NAME. With L-NAME+IND, MAP rose even at 45 min (+5%; P < 0.001 versus baseline) with a 10% rise at 90 min (P < 0.001). Changes in GFR (-13 to -20%), ERPF (-19 to -26%), and UNaV (-51 to -70%) were greater than those with L-NAME+PL or L-NAME+LOS (P < 0.05 to 0.001). With L-NAME+IND+LOS, MAP did not increase, and GFR, ERPF, and UNaV fell much less than with L-NAME+IND alone (P < 0.02 to 0.001) with no differences versus PL or LOS alone. Angiotensin II blockade does not affect renal changes caused by L-NAME but prevents their potentiation by prostaglandin inhibition. Thus, endogenous prostaglandins counteract renal actions of endogenous angiotensin II in Na-repleted humans even when nitric oxide synthesis is inhibited.

Pharmacology of oral combination analgesics: rational therapy for pain

No single analgesic agent is perfect and no single analgesic can treat all types of pain. Yet each agent has distinct advantages and disadvantages compared to the others. Hence, clinical outcomes might be improved under certain conditions with the use of a combination of analgesics, rather than reliance on a single agent. A combination is most effective when the individual agents act through different analgesic mechanisms and act synergistically. By activating multiple pain-inhibitory pathways, combination analgesics can provide more effective pain relief for a broader spectrum of pain, and might also reduce adverse drug reactions. This overview highlights the therapeutic potential of combining analgesic medications with different mechanisms of action, particularly a nonsteroidal anti-inflammatory drug (NSAID) or acetaminophen with an opioid or tramadol.

Cox-2 inhibitors and other nonsteroidal anti-inflammatory drugs in the treatment of pain in the elderly

Nonsteroidal anti-inflammatory drugs (NSAIDs) are among the most commonly prescribed therapies for acute and chronic pain in the elderly. NSAIDs are effective in treating many disorders, but their use often is limited by toxicities, especially gastrointestinal and renal toxicity. COX-2 inhibitors are a major therapeutic advance, providing the analgesic and anti-inflammatory activity of NSAIDs, with a significant improvement in gastrointestinal safety. These new agents may be ideal therapies for older patients at risk for NSAID-related gastrointestinal toxicity.

Vasorelaxant effects of a nitric oxide-releasing aspirin derivative in normotensive and hypertensive rats

1. Nonsteroidal anti-inflammatory drugs have been reported to exacerbate hypertension and to interfere with the effectiveness of some anti-hypertensive therapies. In this study, we tested the effects of a gastric-sparing, nitric oxide-releasing derivative of aspirin (NCX-4016) on hypertension in rats. 2. Hypertension was induced by administering L-NAME in the drinking water (400 mg l(-1)). Groups of rats were treated daily with aspirin, NCX-4016 or vehicle. 3. NCX-4016 significantly reduced blood pressure relative to the aspirin-treated group over the 2-week period of treatment. Aspirin and, to a lesser extent, NCX-4016 suppressed whole blood thromboxane synthesis. 4. In anaesthetized rats, acute intravenous administration of NCX-4016 caused a significant fall in mean arterial pressure in hypertensive rats, but was devoid of such effects in normotensive controls. 5. In vitro, NCX-4016 relaxed phenylephrine-pre-contracted aortic rings obtained from both normotensive and hypertensive rats, and significantly reduced their responsiveness to the contractile effects of phenylephrine. 6. These results suggest that NCX-4016 reduces blood pressure in hypertensive rats, not simply through the direct vasodilatory actions of the nitric oxide released by this compound, but also through possible interference with the effects of endogenous pressor agents. These properties, added to its anti-thrombotic effects, suggest that NCX-4016 may be a safer alternative to aspirin for use by hypertensive patients.

The effectiveness and toxicity of cyclosporin A in rheumatoid arthritis: longitudinal analysis of a population-based registry

OBJECTIVE

To determine factors associated with response or toxicity to cyclosporin A (CSA) in a population-based inception cohort with rheumatoid arthritis (RA).

METHODS

Prospectively collected longitudinal measures including tender joint count (JC), duration of morning stiffness (MS), systolic and diastolic blood pressure (SBP, DBP), and serum creatinine (SCr) were modeled using generalized estimating equations. Survival methods were used to estimate CSA continuation time and its determinants.

RESULTS

Of 133 patients (75% female, median RA duration 13 years), 37 discontinued CSA because of ineffectiveness (19) or because of toxicity (18) including increased SCr in 10, hypertension in 4, infections in 3, and gingival hyperplasia in 1. Patients remained on CSA a median of 75 months (95% confidence interval [CI] 38-112). Those receiving concomitant methotrexate (MTX) were more than 4 times as likely to continue on CSA therapy (hazard ratio 0.22, 95% CI 0.10-0.94). A lower final JC was predicted by a longer CSA treatment duration (relative risk [RR] 0.99 per month, 95% CI 0.98-0.99) and concomitant MTX therapy (RR 0.79, 95% CI 0.63-0.99); decreased MS was predicted only by longer CSA treatment duration (reduction of 2.0 minutes per month, 95% CI 1.1-3.0). Each previous disease-modifying antirheumatic drug (DMARD) exposure predicted a rise in SCr (35 micromole/liter, 95% CI 22-48), SBP (7.2 mm Hg, 95% CI 2.7-11.7), and DBP (3.8 mm Hg, 95% CI 3.0-6.4).

CONCLUSIONS

Combination CSA/MTX prolongs therapy and reduces JC. Long-term CSA treatment was fairly well tolerated. Previous DMARD use appears to be a determinant for the development of toxicity.

Acute effects of the anti-inflammatory cyclooxygenase-2 selective inhibitor, flosulide, on renal plasma flow and glomerular filtration rate in rats

Nephrotoxicity of nonsteroidal anti-inflammatory drugs is associated with other risk factors (volume-depletion) and may be secondary to functional changes mediated by the inhibition of renal cyclooxygenases. Acute anti-inflammatory doses of flosulide and indomethacin were determined on carrageenan paw edema and its effects on renal plasma flow (RPF) and glomerular filtration rate (GFR) were studied in normovolemic and hypovolemic rats. In normovolemic rats, flosulide increased RPF and GFR (25 mg/kg) and indomethacin (5-10 mg/kg) was without effect. Volume-depleted rats were obtained by oral furosemide (32 mg/kg), urinary eicosanoids were determined. After furosemide, plasma volume, RPF and GFR and PGE2 decreased. Treatment of hypovolemic rats with flosulide (5-25 mg/kg) or indomethacin 10 mg/kg reduced RPF and GFR. Flosulide at 5 mg/kg reduced 6-keto-PGF1alpha whereas at 25 mg/kg and after indomethacin at 10 mg/kg a fall in 6-keto-PGF1alpha and TXB2 appeared. Our data suggest that acute COX-2 selective inhibition may alter renal function.

Cyclooxygenase-2--specific inhibitors and cardiorenal function: a randomized, controlled trial of celecoxib and rofecoxib in older hypertensive osteoarthritis patients

BACKGROUND

Arthritis and hypertension are common comorbid conditions affecting elderly adults. Use of nonsteroidal anti-inflammatory drugs in patients treated with antihypertensive medication can lead to destabilization of blood pressure control and other cardiorenal events. The potential for similar interactions with cyclooxygenase-2-specific inhibitors has not been fully explored. The authors evaluated the cardiorenal safety of two new cyclooxygenase-2-specific inhibitors, celecoxib and rofecoxib.

METHODS

This study was a 6-week, randomized, parallel-group, double-blind trial in patients with osteoarthritis who were > or =65 years of age and were taking antihypertensive agents. Patients received once-daily celecoxib 200 mg or rofecoxib 25 mg. The primary endpoints were the development of edema, changes in systolic blood pressure, and changes in diastolic blood pressure as measured at any time point in the study. Measurements occurred at baseline and after 1, 2, and 6 weeks of treatment.

FINDINGS

Eight hundred ten patients received study medication (celecoxib, n = 411; rofecoxib, n = 399). Nearly twice as many rofecoxib- compared with celecoxib-treated patients experienced edema (9.5% vs. 4.9%, P = 0.014). Systolic blood pressure increased significantly in 17% of rofecoxib- compared with 11% of celecoxib-treated patients (P = 0.032) at any study time point. Diastolic blood pressure increased in 2.3% of rofecoxib- compared with 1.5% of celecoxib-treated patients (P = 0.44). At week 6, the change from baseline in mean systolic blood pressure was +2.6 mmHg for rofecoxib compared with -0.5 mmHg for celecoxib (P = 0.007).

CONCLUSIONS

Patients taking antihypertensive therapy and receiving cyclooxygenase-2-specific inhibitors should be monitored for the development of cardiorenal events. Patients receiving celecoxib experienced less edema and less destabilization of blood pressure control compared with those receiving rofecoxib.

NSAIDs and the kidney revisited: are selective cyclooxygenase-2 inhibitors safe?

Selective cyclooxygenase-2 (COX-2) inhibitors have provided relief for patients suffering from chronic pain and other inflammatory conditions and have reduced adverse gastrointestinal effects. The documented reduction in gastric erosions, ulcerations, and perforations during the use of COX-2-selective inhibitors raises the question: would the kidney be similarly spared? Our understanding of these enzyme isoforms in the kidney is incomplete. However, kidney tissue seems to possess "constitutive" or homeostatic COX-2 enzyme, suggesting a role for prostaglandins produced by this isoform. In addition, studies evaluating the renal effects of the selective nonsteroidal anti-inflammatory drugs (NSAIDs) are inconclusive, and available data on the renal effects of COX-2-selective inhibitors are conflicting. Inadequate numbers, varied baseline patient characteristics, and different doses and lengths of drug treatment hampers comparison of the small number of clinical investigations available for review. Therefore, this article reviews the role of cyclooxygenase enzyme activity and associated prostaglandins in the kidney and the adverse renal effects of nonselective NSAIDs. We also touch on the COX-1/COX-2 selectivity of NSAIDs, the localization of COX enzymes in kidneys, and clinical studies examining the renal effects of selective COX-2 inhibitors.

COX-2 inhibitors in rheumatoid arthritis

The selective cyclooxygenase 2 (COX-2) inhibitors have emerged as an important option in the treatment of rheumatoid arthritis (RA). Rofecoxib and celecoxib, the selective COX-2 inhibitors currently available, have shown efficacy in reducing symptoms of RA comparable with that of traditional nonsteroidal antiinflammatory drugs (NSAIDs). The primary advantage of selective COX-2 inhibitors relates to reduced gastrointestinal (GI) toxicity. Gastroduodenal ulcers detected by endoscopy are markedly diminished in patients receiving selective COX-2 inhibitors versus those receiving NSAIDs. Moreover, unpublished data indicate that the risk of symptomatic and complicated ulcers is reduced by approximately half in patients prescribed rofecoxib or celecoxib. Despite these encouraging findings, selective COX-2 inhibitors have the potential for important adverse events such as impaired renal function, hypertension, and edema. Furthermore, clinicians must balance the competing demands of reducing GI risk while managing the increasing costs associated with selective COX-2 inhibitor use.

Prospects for changing the burden of nonsteroidal anti-inflammatory drug toxicity

Traditional nonsteroidal anti-inflammatory drugs (NSAIDs) increase the risk of clinically important upper gastrointestinal ulcers and bleeds about fourfold. Other risk factors for these events include advanced age, higher NSAID dose, prior ulcer or bleed, use of anticoagulants, use of corticosteroids, and poor general health. Among NSAID users with more than one risk factor, the incidence of serious ulcer complications may be as high as 4% to 8% per year. NSAIDs may also increase blood pressure and have adverse effects on renal function. NSAID-associated toxicity may be decreased by (1) trying less toxic alternative drugs; (2) using NSAIDs less frequently or at a lower dose; (3) use of cotherapy, such as misoprostol or proton pump inhibitors, to prevent complications; (4) or use of the more selective cyclooxygenase-2 inhibitors. More research is needed to determine which of these strategies or combination of strategies is optimal in terms of patient safety and cost.

Cyclooxygenase-2--specific inhibitors: are they safe?

The basic tenet of the cyclooxygenase-2 (COX-2) hypothesis rests on the fact that sparing of inhibition of COX-1 should result in greater safety than if both COX isoforms are inhibited. This increase in safety should be most evident in those organs and tissues in which COX-1 alone has important, necessary physiologic functions (e.g., the stomach and platelets). Data from large clinical trials are now available to support the superior gastrointestinal safety of COX-2 inhibitors, not only for endoscopic endpoints but also for clinically significant outcomes. Additionally, lack of effect on platelets has been demonstrated at doses many times higher than being used clinically. Unfortunately, the COX-2 inhibitors still retain some of the side effects seen with traditional dual COX inhibitors (nonsteroidal anti-inflammatory drugs), namely, effects on the kidney that may manifest as an increased incidence of hypertension, edema, and associated clinical states. Similarly, effects on reproductive functions, endothelial function, and wound healing are theoretically possible but need to be evaluated in well-controlled clinical trials.