Sulindac is not renal sparing in man

The case for cautious consumption: NSAIDs in chronic kidney disease

PURPOSE OF REVIEW

Strong epidemiological and pathologic evidence associates NSAIDs with kidney disease, both acute and chronic. Hence, the usage of NSAIDs has decreased in patients with, or at risk for, chronic kidney disease (CKD). Coupled with this has been a rise in use of opioids and other non-NSAID alternatives, which do come with significant, and underrecognized, risk of nonrenal adverse events. We review the literature to understand if this shift is appropriate or deleterious.

RECENT FINDINGS

NSAIDs do have a low but tangible risk in causing acute kidney injury, electrolyte imbalances, and increasing blood pressure. However, their role in causing progressive kidney disease is due to long-term usage in high cumulative dosages, and the use of NSAIDs in combination with other agents. Alternatives such as opioids, tramadol, gabapentin and baclofen have weak evidence to support their use and strong evidence to show their harm in patients with CKD.

SUMMARY

Tradeoffs are inherent in using active pharmaceuticals, and NSAIDs are no exception. Balancing potential benefits with possible adverse effects around pain management should be a part of every conversation for patients with kidney disease.

Dosing of antirheumatic drugs in renal disease and dialysis

Many patients with rheumatic diseases have their management complicated by renal problems. Renal failure modifies the metabolism of many drugs, especially by retention. Questions often arise about the effects of renal failure on the handling of drugs commonly used in rheumatology. For which drugs must we be especially concerned about increased toxicity? Patients on chronic dialysis may also need a variety of drugs for rheumatic disease. How are our drugs dialyzed, and which of these can be safety used and how best to use them?Decisions about dosing of rheumatic drugs are often required for the patients with chronic renal insufficiency or on long-term dialysis, although many drugs have not been formally studied in these settings. Patients with renal insufficiency are excluded from most drug trials. Data for some of these drugs have to be extrapolated based on the information available about the pharmacokinetics of the drug.This review addresses dosing of commonly used drugs in rheumatology in patients with chronic renal insufficiency or failure. It is compiled from a MEDLINE search of papers dealing with renal handling of antirheumatic drugs and suggestions for dose adjustments for these drugs. Drugs reviewed include commonly used disease-modifying antirheumatic drugs (DMARDS), drugs used for treatment of gout, commonly used nonsteroidal antnflammatory drugs (NSAIDS) and the newer COX-2 inhibitors.

Combinatorial effect of non-steroidal anti-inflammatory drugs and NF-κB inhibitors in ovarian cancer therapy

Several epidemiological studies have correlated the use of non-steroidal anti-inflammatory drugs (NSAID) with reduced risk of ovarian cancer, the most lethal gynecological cancer, diagnosed usually in late stages of the disease. We have previously established that the pro-apoptotic cytokine melanoma differentiation associated gene-7/Interleukin-24 (mda-7/IL-24) is a crucial mediator of NSAID-induced apoptosis in prostate, breast, renal and stomach cancer cells. In this report we evaluated various structurally different NSAIDs for their efficacies to induce apoptosis and mda-7/IL-24 expression in ovarian cancer cells. While several NSAIDs induced apoptosis, Sulindac Sulfide and Diclofenac most potently induced apoptosis and reduced tumor growth. A combination of these agents results in a synergistic effect. Furthermore, mda-7/IL-24 induction by NSAIDs is essential for programmed cell death, since inhibition of mda-7/IL-24 by small interfering RNA abrogates apoptosis. mda-7/IL-24 activation leads to upregulation of growth arrest and DNA damage inducible (GADD) 45 α and γ and JNK activation. The NF-κB family of transcription factors has been implicated in ovarian cancer development. We previously established NF-κB/IκB signaling as an essential step for cell survival in cancer cells and hypothesized that targeting NF-κB could potentiate NSAID-mediated apoptosis induction in ovarian cancer cells. Indeed, combining NSAID treatment with NF-κB inhibitors led to enhanced apoptosis induction. Our results indicate that inhibition of NF-κB in combination with activation of mda-7/IL-24 expression may lead to a new combinatorial therapy for ovarian cancer.

Increased renal sodium absorption by inhibition of prostaglandin synthesis during fasting in healthy man. A possible role of the epithelial sodium channels

BACKGROUND

Treatment with prostaglandin inhibitors can reduce renal function and impair renal water and sodium excretion. We tested the hypotheses that a reduction in prostaglandin synthesis by ibuprofen treatment during fasting decreased renal water and sodium excretion by increased absorption of water and sodium via the aquaporin2 water channels and the epithelial sodium channels.

METHODS

The effect of ibuprofen, 600 mg thrice daily, was measured during fasting in a randomized, placebo-controlled, double-blinded crossover study of 17 healthy humans. The subjects received a standardized diet on day 1, fasted at day 2, and received an IV infusion of 3% NaCl on day 3. The effect variables were urinary excretions of aquaporin2 (u-AQP2), the beta-fraction of the epithelial sodium channel (u-ENaCbeta), cyclic-AMP (u-cAMP), prostaglandin E2 (u-PGE2). Free water clearance (CH2O), fractional excretion of sodium (FENa), and plasma concentrations of vasopressin, angiotensin II, aldosterone, atrial-, and brain natriuretic peptide.

RESULTS

Ibuprofen decreased u-AQP2, u-PGE2, and FENa at all parts of the study. During the same time, ibuprofen significantly increased u-ENaCbeta. Ibuprofen did not change the response in p-AVP, u-c-AMP, urinary output, and free water clearance during any of these periods. Atrial-and brain natriuretic peptide were higher.

CONCLUSION

During inhibition of prostaglandin synthesis, urinary sodium excretion decreased in parallel with an increase in sodium absorption and increase in u-ENaCbeta. U-AQP2 decreased indicating that water transport via AQP2 fell. The vasopressin-c-AMP-axis did not mediate this effect, but it may be a consequence of the changes in the natriuretic peptide system and/or the angiotensin-aldosterone system

TRIAL REGISTRATION

Clinical Trials Identifier: NCT00281762.

A novel pathway involving melanoma differentiation associated gene-7/interleukin-24 mediates nonsteroidal anti-inflammatory drug-induced apoptosis and growth arrest of cancer cells

Numerous studies show that nonsteroidal anti-inflammatory drugs (NSAIDs) are effective in chemoprevention or treatment of cancer. Nevertheless, the mechanisms underlying these antineoplastic effects remain poorly understood. Here, we report that induction of the cancer-specific proapoptotic cytokine melanoma differentiation associated gene-7/interleukin-24 (MDA-7/IL-24) by several NSAIDs is an essential step for induction of apoptosis and G(2)-M growth arrest in cancer cells in vitro and inhibition of tumor growth in vivo. We also show that MDA-7/IL-24-dependent up-regulation of growth arrest and DNA damage inducible 45 alpha (GADD45alpha) and GADD45gamma gene expression is sufficient for cancer cell apoptosis via c-Jun NH(2)-terminal kinase (JNK) activation and growth arrest induction through inhibition of Cdc2-cyclin B checkpoint kinase. Knockdown of GADD45alpha and GADD45gamma transcription by small interfering RNA abrogates apoptosis and growth arrest induction by the NSAID treatment, blocks JNK activation, and restores Cdc2-cyclin B kinase activity. Our results establish MDA-7/IL-24 and GADD45alpha and GADD45gamma as critical mediators of apoptosis and growth arrest in response to NSAIDs in cancer cells.

Effects of nonsteroidal anti-inflammatory drugs on renal function: focus on cyclooxygenase-2-selective inhibition

Nonsteroidal anti-inflammatory drugs (NSAIDs) can affect renal function in a variety of ways. The most important clinical effects are decreased sodium excretion, decreased potassium excretion, and declines in renal perfusion. Decreased sodium excretion can result in weight gain, peripheral edema, attenuation of the effects of antihypertensive agents, and rarely precipitation of chronic heart failure. Hyperkalemia can occur to a degree sufficient to cause cardiac arrhythmias. Renal function can decline sufficiently enough to cause acute renal failure. Risk factors for all of these effects have been identified, allowing prospective identification of patients at risk with institution of appropriate precautionary measure. All NSAIDs seem to share these adverse effects. Preliminary data from cyclooxygenase-2-selective inhibitors suggest that they also affect renal prostaglandins. Therefore, the same cautions should be exercised with their use as with traditional NSAIDs.

Renal hemodynamic effects of nabumetone, sulindac, and placebo in patients with osteoarthritis

We assessed the effects of nabumetone, sulindac, and placebo on renal function and renal excretion of vasodilatory prostaglandins in older female patients (age >50 years) with osteoarthritis and normal renal function. Using a prospective, crossover design, we compared the effects of nabumetone 2000 mg/d and sulindac 400 mg/d with placebo on glomerular filtration rate (GFR), renal plasma flow (RPF), and urinary excretion of prostaglandin E2 and 6-keto-prostaglandin F1alpha in 12 patients. Urinary excretion of vasodilatory prostaglandins was not decreased after 14 days of treatment with either nabumetone or sulindac. Likewise, treatment with nabumetone or sulindac did not significantly alter renal function compared with placebo. There were no differences in mean changes in GFR or RPF from baseline after treatment with nabumetone or sulindac compared with placebo. The mean (+/- SD) changes in GFR from baseline were 0%+/-8% in patients receiving nabumetone, -8%+/-15% in patients receiving sulindac, and -7%+/-15% in patients receiving placebo. The results of this study demonstrate that treatment with nabumetone or sulindac caused no deterioration in renal function in older female patients with osteoarthritis and normal renal function.

Effect of nabumetone on hemostasis during arthroscopic knee surgery

The known effects of commonly used nonsteroidal anti-inflammatory drugs (NSAIDs) on hemostatic parameters have led to concern over their use in the perioperative period. Nabumetone, unlike other NSAIDs, has little effect on collagen-induced platelet aggregation. To evaluate the effect of nabumetone 2000 mg daily on other hemostatic parameters (e.g., bleeding time, prothrombin time, and partial thromboplastin time) in the clinical setting, this double-masked study was conducted in patients with osteoarthritis undergoing arthroscopic knee surgery. After a 1-week placebo washout period, 58 patients were randomized to receive nabumetone and 53 were randomized to receive placebo. They were assessed before surgery (after 1 to 2 weeks of treatment) and again after surgery (after an additional 3 weeks of treatment). The study was designed to have 90% power to show equivalence in bleeding time to within 1.5 minutes, a difference assumed to be of no clinical importance. No meaningful differences were observed between the groups in any of the measured hemostatic parameters. Before surgery, the bleeding time increased by only 0.3 minutes with nabumetone and decreased by 0.2 minutes with placebo. The mean (+/- SD) difference between the groups in change from baseline was 0.5 +/- 0.3 minutes. After surgery, the changes were 0.1 minutes and 0.0 minutes, respectively, and the difference between groups was 0.2 +/- 0.3 minutes. These differences were neither statistically nor clinically significant, and maximum individual increases were similar in each group. Furthermore, there were no reports of abnormal bleeding in the operative knees. The results of this study show that nabumetone had little or no effect on hemostasis and suggest that this drug can be used safely in the perioperative period.

Clinical pharmacokinetics of sulindac. A dynamic old drug

Sulindac is a nonsteroidal anti-inflammatory drug (NSAID) of the indene acetic acid class. The absorption of sulindac is rapid when given orally. Sulindac is reversibly metabolised to sulindac sulphide which has anti-inflammatory and analgesic properties and is irreversibly metabolised to sulindac sulphone which has been suggested to possess antiproliferative effects against tumours. Sulindac and its sulphide and sulphone metabolites bind extensively to plasma albumin. Sulindac is eliminated following bio-transformation; sulindac and sulindac sulphone and their respective glucurooconjugated metabolites are excreted in urine; however only a small amount of the sulindac sulphide metabolite is eliminated in urine. Following long term twice daily administration both sulindac and its metabolites accumulate in plasma. Both patients with cirrhosis and the elderly demonstrate elevated concentrations of all species upon long term sulindac administration as compared with a single dose. The disposition of sulindac and its metabolites may be tied to renal function. In end-stage renal disease, increased free fractions of all species and accumulation of the sulphide and sulphone metabolites, and to a lesser extent sulindac, occurs. Significant drug interactions have been demonstrated for dimethylsulphoxide, cyclosporin, furosemide (frusemide), hydrochlorothiazide, methotrexate and cholestyramine.

Comparative effects of nabumetone, sulindac, and indomethacin on urinary prostaglandin excretion and platelet function in volunteers

Nonsteroidal antiinflammatory drugs differ with respect to their effects on prostaglandin metabolism in various tissues, a property that may be partly responsible for some of the differences in the pharmacologic activities and side-effect profiles that are associated with their use. The effects of nabumetone on urinary prostaglandin excretion have not been reported. Fourteen healthy females, age 21-43 years, were treated with nabumetone (NAB) 1000 mg daily, sulindac (SUL) 200 mg every 12 hours, and indomethacin (IND) 50 mg every 12 hours for 7 days in a randomized period-balanced crossover study. The effects of drug treatment on urinary prostaglandin excretion (PGE2, 6-keto-PGF1 alpha, PGF2 alpha, thromboxane [TX] B2) and platelet function (collagen-induced whole blood platelet aggregation [CIPA] and template bleeding time) were determined on day 1 and day 7. For each treatment regimen, mean baseline urinary PG excretion values were comparable for each prostanoid, but the pattern of excretion differed in response to each drug. Treatment with NAB significantly increased the urinary excretion rates of PGE2 and PGF2 alpha, but 6-keto-PGF1 alpha and TXB2 excretion were unchanged. IND treatment did not result in a significant change in PGE2 excretion but did significantly reduce urinary 6-keto-PGF1 alpha and TXB2 excretion rates. Reduced excretion of PGF2 alpha was observed on both study days during treatment with IND and SUL. SUL treatment also resulted in increased urinary PGE2 excretion while significantly reducing 6-keto-PGF1 alpha excretion on day 7. Significant differences were observed between the NAB and SUL regimens with respect to PGF2 alpha excretion and between the NAB and SUL regimens for PGE2, PGF2 alpha, 6-keto-PGF alpha 1 (on day 1 only) and TXB2 (on day 1 only). Neither NAB nor SUL caused inhibition of CIPA or bleeding time although platelet aggregation was inhibited during IND treatment. That NAB treatment was neither associated with alterations in platelet function nor decreases in the urinary excretion of the vasodilatory prostaglandins, PGE2 and 6-keto-PGF1 alpha, suggests that NAB possesses renal sparing properties.

Nonsteroidal anti-inflammatory drugs and antihypertensives

Approximately 60 million people in the United States have hypertension (BP greater than or equal to 140/90 mm Hg), 40 million have arthritis clinically suitable for nonsteroidal anti-inflammatory drug (NSAID) therapy, and millions take NSAIDs for nonarthritic conditions, creating considerable potential for concomitant administration of NSAIDs and antihypertensive agents. It is estimated that more than 20 million people are on concurrent therapy. Most NSAIDs produce mild elevations of normal blood pressure levels and can partially or completely antagonize the effects of many antihypertensive drugs. The effect on blood pressure can vary from no effect to hypertensive crisis. In pooled studies, the average increase in mean arterial pressure was 10 mm Hg, and duration was short-lived or chronic. Significant interactions occur in about 1% of patients per year. The risk is greatest in the elderly, blacks, and patients with low-renin hypertension. NSAIDs may block the antihypertensive effects of thiazide and loop diuretics, beta-adrenergic blockers, alpha-adrenergic blockers, and angiotensin-converting enzyme inhibitors. No interactions have been reported with centrally acting alpha agonists or the calcium channel blockers. The mechanism of the hypertensive effects of NSAIDs seem primarily related to their ability to block the cyclo-oxygenase pathway of arachidonic acid metabolism, with a resultant decrease in prostaglandin formation. The prostaglandins are important in normal modulation of renal and systemic vascular dilatation, glomerular filtration, tubular secretion of salt and water, adrenergic neurotransmission, and the renin-angiotensin-aldosterone system. Blockade of salutary effects of prostaglandins by NSAIDs results in a complex series of events culminating in attenuation of the effects of many antihypertensive agents. High-risk patients treated with NSAIDs should be identified and have blood pressure, renal function, and serum potassium frequently monitored.

The effects of sulindac and diclofenac in essential hypertension controlled by treatment with a beta blocker and/or diuretic

A placebo-controlled, double blind crossover study of the non-steroidal anti-inflammatory drugs (NSAIDs) sulindac and diclofenac was conducted in 16 patients with essential hypertension that was controlled by treatment with a beta blocker, a diuretic or co-administration of both. In 4 cases, another antihypertensive agent (prazosin or verapamil) was also co-administered. In every patient, plasma creatinine concentration was less than 0.14 mmol/l (normal range 0.07-0.12 mmol/l). Sulindac and diclofenac were each given for 7 weeks. Diclofenac caused a decrease of borderline significance in plasma aldosterone concentration. Neither NSAID altered the mean values for systolic or diastolic blood pressure, body weight, plasma electrolyte concentrations, urate clearance, creatinine clearance or plasma renin activity. However, rises in plasma creatinine concentration and falls in creatinine clearance occurred during NSAID therapy in three individual subjects. No significant differences were observed in this study between the effects on renal function or blood pressure of sulindac and diclofenac, both of which appear not to interfere with the antihypertensive actions of beta blockers and diuretics.

Effects of non-steroidal anti-inflammatory drugs on prostacyclin and thromboxane biosynthesis in patients with mild essential hypertension

1. The effects of non-steroidal anti-inflammatory drugs (NSAID) on prostacyclin and thromboxane biosynthesis and on blood pressure were determined in 46 patients with mild essential hypertension. Patients who had abstained from antihypertensive therapy for 2 weeks before study were treated with either aspirin, ibuprofen, sulindac or placebo for 7 days. 2. Excretion rates of 2,3-dinor-6-oxo-prostaglandin (PG) F1 alpha, 6-oxo-PGF1 alpha, 2,3-dinorthromboxane (TX) B2 and TXB2 were measured as indices of prostacyclin and TXA2 biosynthesis. Samples were assayed using immunoaffinity chromatography and gas chromatography/electron capture chemical ionisation mass spectrometry. 3. Aspirin and ibuprofen reduced urinary excretion of all prostacyclin- and thromboxane-derived products. Sulindac inhibited excretion of 2,3-dinor-6-oxo-PGF1 alpha, 6-oxo-PGF1 alpha and 2,3-dinor-TXB2, but had no significant effect on TXB2. 4. Systolic blood pressure increased in the ibuprofen-treated group when compared with the placebo group. There were no other significant changes in systolic or diastolic pressure in any of the treatment groups. Among the patients as a whole, there was a significant negative correlation between change in blood pressure and change in excretion of the prostacyclin-derived but not of the thromboxane-derived products. 5. We conclude that, in patients with mild essential hypertension, neither sulindac nor aspirin (in the doses used) selectively spares prostacyclin biosynthesis by the kidney. The significant relationship between increase in blood pressure and reduction in prostacyclin biosynthesis favours the possibility that in individuals who become hypertensive, prostacyclin biosynthesis determines, in part, the severity of the hypertensive state.

The effects of ibuprofen and indomethacin on renal function in the presence and absence of frusemide in healthy volunteers on a restricted sodium diet

1. Since salt depletion stimulates the renal prostaglandin system to maintain renal function, the effects of indomethacin and ibuprofen upon renal haemodynamics, electrolyte excretion and renin release were examined in eight healthy male volunteers on a salt restricted diet, before and after frusemide administration. 2. Neither indomethacin (50 mg) nor ibuprofen (400 mg and 800 mg) affected renal blood flow, glomerular filtration rate or electrolyte excretion before frusemide. 3. Renal blood flow and glomerular filtration rate were significantly increased in the first 20 min after frusemide. These changes were significantly attenuated by indomethacin compared with placebo and ibuprofen 400 mg. Frusemide-induced diuresis but not natriuresis was inhibited by all treatments. 4. Both nonsteroidal agents inhibited equally the rise in renin activity seen after frusemide. 5. In this group of healthy volunteers on a salt restricted diet, ibuprofen and indomethacin had no detrimental effects on renal function in the absence of frusemide. The changes in renal haemodynamics due to frusemide were suppressed more by indomethacin than by ibuprofen, probably reflecting the more potent nature of indomethacin as an inhibitor of prostaglandin synthesis.

Clinical differences among nonsteroidal antiinflammatory drugs: implications for therapeutic substitution in ambulatory patients

The practice of therapeutic substitution, i.e., replacing one drug with another chemically different drug from the same therapeutic class, represents an important therapeutic modification with potential clinical significance far beyond that of generic substitution. Adverse consequences following therapeutic substitution of nonsteroidal antiinflammatory drugs (NSAID) is of special concern because of substantial differences among these agents in pharmacokinetic, pharmacological, and clinical properties. Therapeutic substitution of NSAID for ambulatory patients may result in compromised clinical outcome because (1) patient response is unpredictable and selection of the optimal agent must be tailored for each patient; (2) substantial differences exist in adverse reaction profiles; (3) drug interaction studies are lacking; and (4) selection of an agent must be individualized to ensure compliance with the dosing regimen. Cost savings achieved through therapeutic substitution of NSAID may be lost by additional overall treatment costs due to adverse reactions or suboptimal therapy. The occurrence of adverse or suboptimal effects in ambulatory patients is more likely if NSAID are substituted without full knowledge of the patient's medical history and clinical status. Communication between the pharmacy and prescribing physician regarding a patient's specific needs is essential for rational substitution among NSAID.

Interaction and selection of therapeutic agents in the elderly: NSAIDs and the ageing kidney

Nonsteroidal anti-inflammatory drugs (NSAIDs) represent a commonly used class of therapeutic agents in rheumatic disorders, especially in our elderly population. Although their mechanism of anti-inflammatory action may be multifarious, global prostaglandin blockade, especially in the elderly, is responsible for many of the recognized adverse effects. Complications of NSAID gastropathy represent the most serious adverse effect, its frequency becoming an alarming health problem. Various nephrotoxicity syndromes seen with NSAID use in the elderly are less prevalent and less often recognized. Commonest is reversible, hemodynamically mediated renal insufficiency due to prostaglandin blockade. Potential differences among NSAIDs are reviewed in light of the concept of compartmentalized renal prostaglandin blockade. A framework is developed for the clinical application of these potential differences, especially in the treatment of elderly patients. Along a continuum of increasing risk factors for NSAID nephrotoxicity or increasing NSAID dose, there likely exists an intermediate therapeutic window where differences among NSAIDs are most relevant.

The basis for variability of response to anti-rheumatic drugs

The reasons for variability of response to anti-rheumatic drugs are myriad. All the factors that contribute to kinetic variability, for example, contribute to differences in response between individuals. Thus, differences in drug formulation, protein binding, drug metabolism and excretion, all contribute to variable responses. Further, factors which contribute to differential clinical response/toxicity must be considered. Here, age, gender, genetic background, weight, concomitant diseases and numerous environmental factors come into play. Among the environmental factors are such diverse elements as smoking, activity and diet. Finally our ability to measure change, be it in response or toxicity, is limited, introducing apparent variability (as much as real variability) into the equation. While we cannot, at present, delineate the contribution of each factor to individual variability, it is hoped that systematic, persistent effort will help us understand and then control these elements, leading to improved ability to individualize therapy and decrease the variability of response to anti-rheumatic drugs.

Deactivation of sulindac-sulphide by human renal microsomes

The renal metabolism of sulindac-sulphide was studied in subcellular fractions from human kidney. It was shown that renal microsomes, in the presence of NADPH, effectively catalyzed the sulphoxidation of sulindac-sulphide. Also the mitochondrial fraction catalyzed the reaction but at a ten-fold lower rate than the microsomes. Carbon monoxide, metyrapone and n-octylamine did not inhibit renal sulphoxidation of sulindac-sulphide and the reaction could occur in a monooxygenase containing fraction free from NADPH-cytochrome P-450 reductase. Hydroxylation of lauric acid was studied in microsomes and in the purified monooxygenase containing fraction under the same experimental condition as sulindac-sulphide sulphoxidation. Lauric acid is a substrate known to be metabolized by a renal cytochrome P-450 to 11 and 12-hydroxylated products. This reaction was sensitive to carbon monoxide and did not occur in the absence of NADPH cytochrome P-450 reductase. Based on these results we conclude that cytochrome P-450 plays at the most a limited role in human kidney metabolism of sulindac-sulphide. In contrast, sulphoxidation of sulindac-sulphide was substantially reduced in the presence of methimazole suggesting a role of the flavin-containing monooxygenase in the renal biotransformation of sulindac-sulphide in man.

Nonsteroidal antiinflammatory drug-induced renal dysfunction related to inhibition of renal prostaglandins

This article reviews the role of prostaglandins (PG) in maintaining renal function in the face of vasoconstrictive substances and decreased renal blood flow. Inhibition of the synthesis of renal PG by nonsteroidal antiinflammatory drugs (NSAID) may lead to the development of hemodynamically induced renal dysfunction in patients with a decreased effective plasma volume or chronic renal insufficiency. The importance of stimulation of renal PG activity to the action of diuretics and a pharmacodynamic mechanism for NSAID-induced diuretic resistance are presented. Evidence for the relative selectivity of sulindac in inhibiting systemic PG without inhibiting renal PG is also reviewed. Inhibition of renal PG synthesis has been postulated to be a contributing factor for other forms of NSAID-induced renal dysfunction (interstitial nephritis, analgesic-associated nephropathy). The relationship between renal PG inhibition by NSAID and these syndromes is briefly discussed. Considering the frequent use of NSAID, it is important that practitioners are aware of the mechanisms whereby patients may develop NSAID-induced renal dysfunction and that they are able to identify patients at risk.

Reversible acute decrease in renal function by NSAIDs in cirrhosis

The effects of sulindac were compared with those of ibuprofen or naproxen on creatinine clearance and urinary prostanoids in patients with severe alcoholic cirrhosis. Sulindac caused acute declines in all renal parameters in four of five patients. The effect occurred with serum concentrations of the active sulfide metabolite comparable to those in patients with no hepatic impairment. The patient who was not affected had less effects on urinary PGE2 and TxB2 and no effect on 6-keto PGF1 alpha. In this patient, dosing with ibuprofen caused pronounced declines in all urinary prostanoids and a decrease in creatinine clearance. Two other patients treated with ibuprofen and one treated with naproxen also suffered decrements in all parameters. In conclusion, sulindac had suppressant effects on renal prostanoids associated with declines in creatinine clearance in these patients with cirrhosis, indicating a need for similar cautions with its use as with other NSAIDs.

The effects of naproxen and sulindac on renal function and their interaction with hydrochlorothiazide and piretanide in man

We have studied the effect of a single dose challenge of naproxen (500 mg) and sulindac (200 mg) on renal function in five volunteers, and the effect of a single dose challenge of the thiazide, hydrochlorothiazide (100 mg), and loop diuretic, piretanide (6 mg) on renal function when the diuretics were given alone or when superimposed on chronic therapy of either naproxen or sulindac. None of the nonsteroidal anti-inflammatory drug (NSAID) or diuretic exposures significantly influenced glomerular filtration rate, as measured by creatinine clearance. Over the first 4 h of the study, both naproxen and sulindac reduced fractional excretion of sodium by approximately 50%. Sulindac also caused a significant uricosuria whilst naproxen promoted urate retention. Similar changes were observed over 8 h. Superimposition of either hydrochlorothiazide or piretanide on top of chronic sulindac therapy resulted in a blunting of the natriuresis by approximately 30% compared to when these diuretics were given alone: the action of the diuretics was unchanged by naproxen. Sulindac pretreatment did not alter the urinary excretion of either hydrochlorothiazide or piretanide; naproxen did not alter hydrochlorothiazide excretion. On the basis of these findings, it is concluded that NSAIDs exert direct tubular effects that do not necessarily interfere with the delivery of diuretics to their sites of action within the nephron.

Inhibitory effect of sulindac on prostaglandin synthesis in cultured renal and vascular cells

Sulindac, a non-steroidal anti-inflammatory drug (NSAID), is said to be less toxic to the kidney than the other NSAIDs. To examine this hypothesis we investigated the effects of sulindac and other NSAIDs on prostaglandin (PG) synthesis in cultured rat renal and vascular cells. In all cells examined, indomethacin, tiaprofenic acid, aspirin and ibuprofen (3.3 x 10(-5)-3.3 x 10(-4)M) inhibited both basal and arachidonic acid (AA)-stimulated PGE2 or PGI2 synthesis (measured as 6-keto-PGF1 alpha), while sulindac (3.3 x 10(-5)-3.3 x 10(-4)M) inhibited both basal and AA-stimulated PGE2 synthesis in renal papillary collecting tubule cells but not basal PGI2 synthesis in vascular smooth muscle cells or AA-stimulated PGE2 synthesis in glomerular mesangial cells. The order of potency for NSAIDs to inhibit PG synthesis in these cells was tiaprofenic acid, indomethacin greater than ibuprofen, aspirin greater than sulindac. It is suggested that the prodrug sulindac is biotransformed to the active sulfide in the intact kidney cells, which may be less prominent in glomerular mesangial or vascular smooth muscle cells.

Renal side effects of nonsteroidal antiinflammatory drugs: clinical relevance

Nonsteroidal antiinflammatory drugs (NSAIDs) induce a variety of renal side effects. We review their prevalence and clinical relevance, and identify the patients who are most at risk for these complications. NSAIDs induce hemodynamic renal failure in states of compromised renal perfusion and in the presence of a preexisting nephropathy. Association of triamterene and indomethacin is especially nephrotoxic and should be avoided. NSAIDs cause sodium retention and impair the natriuretic effect of diuretics: this side effect is clinically relevant in edema-forming states. Hyperkalemia induced by NSAIDs is harmful in case of renal failure and hypoaldosteronism. NSAIDs may induce an acute interstitial nephritis often associated with the nephrotic syndrome; the event is rare and unpredictable, and mainly propionic acid derivatives have been incriminated. NSAIDs are reported to attenuate the hypotensive effect of various drugs; further studies are warranted to better delineate the clinical relevance of this observation.

Effects of 1 gram oral or intravenous aspirin on urinary excretion of thromboxane B2 and 6-keto-PGF1 alpha in healthy subjects

Aspirin inhibits cyclo-oxygenase, thus preventing prostanoids formation. After oral administration aspirin is hydrolysed to inactive salicylate partly within the gastrointestinal tract, partly during first pass in the liver, partly in the circulation by plasma esterases. Intravenous aspirin, in contrast, mainly undergoes plasma esterase-catalysed deacetylation. Six healthy male subjects were given 1 g aspirin orally and intravenously two weeks apart according to a cross-over randomized design. Whereas serum TxB2 generation reflecting platelet cyclo-oxygenase activity was suppressed by aspirin by both routes, urinary excretion of TxB2 and 6-keto-PGF1 alpha was not affected by oral aspirin, but was partially though significantly reduced by the i.v. drug. Drug disposition seems therefore to be essential in determining the "biochemical selectivity" of aspirin as related to platelet and renal prostanoids generation.

Renal effects of nonsteroidal anti-inflammatory drugs in chronic glomerular disease

In contrast to a variety of clinical conditions characterized by ineffective circulatory volume, chronic glomerular disease is not usually associated with increased circulating levels of vasoconstrictor hormones. However, a reduction in glomerular prostacyclin production can possibly account for the prostaglandin dependence of renal function in these patients by virtue of the enhanced constrictor effects of angiotensin II on glomerular arterioles and mesangium. The reduction of renal function induced by a nonselective cyclo-oxygenase inhibitor is inversely related to the basal prostacyclin production. Increased renal synthesis of vasoconstrictor thromboxane A2, as noted in patients with systemic lupus erythematosus, might contribute to the cyclo-oxygenase dependence of renal function. Aspirin as well as a variety of structurally unrelated nonsteroidal anti-inflammatory drugs reduce renal function in systemic lupus erythematosus patients. However, the functional consequences of renal cyclo-oxygenase inhibition are partially attenuated in patients with lupus nephritis vis-à-vis other forms of chronic glomerular disease because of concomitant suppression of enhanced glomerular thromboxane A2 production. Animal data consistent with a prevailing functional significance of vasodilator prostaglandins have also been reported. Short-term administration of sulindac at the recommended dosage is relatively safe in patients with chronic glomerular disease because of selective sparing of glomerular cyclo-oxygenase activity. The long-term consequences of selective versus nonselective cyclo-oxygenase inhibition remain to be established in humans. The beneficial effects of a combination of aspirin and dipyridamole in slowing the deterioration of renal function in patients with membranoproliferative glomerulonephritis does provide a rationale for exploring the effects of low-dose aspirin (i.e., 0.5 to 1.0 mg/kg per day), which most effectively suppresses platelet thromboxane A2 production without interfering with renal prostacyclin synthesis.

Interaction of nonsteroidal anti-inflammatory drugs with antihypertensive and diuretic agents. Control of vascular reactivity by endogenous prostanoids

Indomethacin and some other nonsteroidal anti-inflammatory drugs partially antagonize the blood pressure lowering effect of drugs used to treat hypertension. They can also produce a mild elevation of blood pressure in normotensive individuals. The elevated arterial pressure caused by these agents is associated with increases in the vascular resistance of mainly the renal and splanchnic beds. This may be due to direct inhibition of the synthesis of vasodilator prostanoids, or it may be due to indirect potentiation of the action of the sympathetic nervous system or of angiotensin II. Nonsteroidal anti-inflammatory drugs also cause renal retention of sodium and this probably contributes to their hypertensive effects. In humans, the sodium retention may involve increased reabsorption in the proximal tubule. Although a direct tubular action is possible, these drugs may change proximal sodium reabsorption by their vascular effects. However, the exact mechanism is not understood. These interactions are clinically significant and may complicate the treatment of common diseases.

Effects of nonsteroidal anti-inflammatory drugs in healthy subjects

Nonsteroidal anti-inflammatory drugs inhibit cyclo-oxygenase activity and thereby reduce prostaglandin synthesis. Studies in humans have used these cyclo-oxygenase inhibitors to examine the role of prostaglandins in controlling renal function. Although short-term studies have demonstrated reductions in effective renal plasma flow, glomerular filtration rate, urinary sodium excretion, and plasma renin activity, long-term administration of nonsteroidal anti-inflammatory drugs does not result in significant or clinically important changes in renal function in normal human subjects. If healthy volunteers are placed on low-sodium diets or treated with diuretics, both renal hemodynamics and salt and water excretion can become prostaglandin-dependent. Studies in normal subjects suggest that sulindac, a nonsteroidal anti-inflammatory drug that undergoes biotransformation in the kidney, does not inhibit renal prostaglandin synthesis or urinary sodium excretion under basal conditions but may impair furosemide-stimulated prostaglandin synthesis and changes in renal function. Doses of sulindac that spare basal renal cyclo-oxygenase do inhibit extrarenal cyclo-oxygenase. The mechanism responsible for this biochemical selectivity of sulindac is not related to a differential sensitivity of the renal cyclo-oxygenase to the active metabolite of sulindac, sulindac sulfide. Sulindac sulfide, in concentrations as low as 1 nM, was equipotent to indomethacin as an inhibitor of prostaglandin E2 synthesis in primary cultures of three renal cell lines. Appropriate clinical use of all nonsteroidal anti-inflammatory drugs, including sulindac, requires careful consideration of risk factors that predispose to nephrotoxicity and careful monitoring when administered to patients at risk.

Drug-drug and drug-disease interactions with nonsteroidal anti-inflammatory drugs

Nonsteroidal anti-inflammatory drugs may cause a number of drug interactions. They can displace other drugs from serum proteins, and some can affect the metabolism or decrease the renal elimination of other drugs. In addition, they can attenuate the pharmacologic effect of other drugs, such as diuretic and antihypertensive agents, without affecting their disposition. Lastly, many disease states and aging can affect the handling of nonsteroidal anti-inflammatory drugs, mandating dose adjustment of some of these agents in certain clinical conditions. Some drugs may require more of these adjustments than others.