Major upper gastrointestinal tract bleeding. Relation to the use of aspirin and other nonnarcotic analgesics

Low-dose acetylsalicylic acid use and the risk of upper gastrointestinal bleeding: a meta-analysis of randomized clinical trials and observational studies

BACKGROUND

Low-dose acetylsalicylic acid (LDA, 75 mg/day to 325 mg/day) is recommended for primary and secondary prevention of cardiovascular events, but has been linked to an increased risk of upper gastrointestinal bleeding (UGIB).

OBJECTIVE

To analyze the magnitude of effect of LDA use on UGIB risk.

METHODS

The PubMed and Embase databases were searched for randomized controlled trials (RCTs) reporting UGIB rates in individuals receiving LDA, and observational studies of LDA use in patients with UGIB. Studies were pooled for analysis of UGIB rates.

RESULTS

Eighteen studies were included. Seven RCTs reported UGIB rates in individuals randomly assigned to receive LDA (n=22,901) or placebo (n=22,923). Ten case-control studies analyzed LDA use in patients with UGIB (n=10,816) and controls without UGIB (n=30,519); one cohort study reported 207 UGIB cases treated with LDA only. All studies found LDA use to be associated with an increased risk of UGIB. The mean number of extra UGIB cases associated with LDA use in the RCTs was 1.2 per 1000 patients per year (95% CI 0.7 to 1.8). The number needed to harm was 816 (95% CI 560 to 1500) for RCTs and 819 (95% CI 617 to 1119) for observational studies. Meta-analysis of RCT data showed that LDA use was associated with a 50% increase in UGIB risk (OR 1.5 [95% CI 1.2 to 1.8]). UGIB risk was most pronounced in observational studies (OR 3.1 [95% CI 2.5 to 3.7]).

CONCLUSIONS

LDA use was associated with an increased risk of UGIB.

Clinical features and risk factors for upper gastrointestinal bleeding in children: a case-crossover study

OBJECTIVE

This population-based survey was conducted to provide a formal description of upper gastrointestinal bleeding (UGIB) in children on a nationwide basis and assess the contribution of risk factors, principally nonsteroidal anti-inflammatory drugs (NSAID).

METHODS

A case-crossover study of UGIB patients aged between 2 months and 16 years was conducted in France. Medical data were collected by physicians, and personal risk factors and exposure to drugs during the month preceding the onset of the bleeding was ascertained by a standardised telephone interview with parents. The odds ratios for UGIB and NSAID was assessed by comparing exposure during the 7 days preceding the date of hospitalisation and the 21st to the 28th days before that date.

RESULTS

A total of 177 children with UGIB were included over 2 years. Eighty-three children had taken at least one NSAID before the index date, among which 58 were ibuprofen, 26 aspirin and nine others. The adjusted odds ratio (OR) of exposure was 8.2 [95% confidence interval (CI) 2.6-26.0] for NSAIDs altogether, and this was 10.0 (95% CI 2.0-51.0) for ibuprofen and 7.3 (95% CI 0.9-59.4) for aspirin. There was no increased risk associated with NSAIDS for oesophageal lesion [OR = 1.0 [(5% CI:0.2-7.2)].

CONCLUSION

The study confirms that UGIB is rare but that some cases may be avoided, as one third of the cases was attributable to exposure to NSAID at doses used for analgesic or antipyretic purposes, which may be attained with alternative therapy. The findings from this study call for more caution in prescribing NSAIDS to children.

Upper gastrointestinal complications among users of paracetamol

Non-steroidal anti-inflammatory drugs (NSAIDs) have been associated with upper gastrointestinal complications such as bleeding or perforation. Paracetamol has been traditionally considered a safer alternative to NSAIDs. In a previous case-control study we found that paracetamol at high doses increased the risk of upper gastrointestinal complications. We proposed to review all studies addressing the association between paracetamol and upper gastrointestinal complications and placed our results in the context of existing literature. We conducted a nested case-control study using the United Kingdom General Practice Research Database during the period between April 1993 and October 1998. Then we performed a systematic review of the literature indexed in MEDLINE published between 1980 and 2004. We identified a total of twelve studies that assessed the association between paracetamol and upper gastrointestinal complications. We used a fixed effects model to calculate a summary estimate of these studies. In the nested case control study, use of paracetamol was associated with a small elevated risk of upper gastrointestinal complications (relative risk (RR), 1.3; 95% confidence interval (CI), 1.1-1.5). The RR was 3.6 (95% CI, 2.6-5.1) among paracetamol users of more than 2 g daily, whereas smaller doses did not increase the risk. Among the twelve studies identified in the systematic review, estimates ranged from 0.2 through 2.0 with a summary estimate of 1.3 (95% CI, 1.2-1.5). Our findings indicate that use of paracetamol at the doses most commonly used confer little or no increased risk of upper gastrointestinal complications. More data are needed to confirm or refute the suggestion that high-dose paracetamol is associated with an increased risk of upper gastrointestinal complications of the same magnitude as the one observed with traditional NSAIDs.

Balancing the gastrointestinal benefits and risks of nonselective NSAIDs

Nonselective nonsteroidal anti-inflammatory drugs (NSAIDs) are among the most widely used classes of medications to treat pain and inflammation. However, gastrointestinal complications associated with NSAIDs are prevalent, largely due to the frequent use of these agents. Adverse events associated with NSAIDs include minor side effects, such as dyspepsia, as well as serious complications, such as bleeding and perforation. Although the probability that any given individual user of an NSAID will suffer a serious gastrointestinal complication is fairly low, widespread patient exposure can translate into a major national health burden. The increasing use of aspirin in the prevention of cardiovascular events and the availability of select over-the-counter NSAIDs represent additional challenges to clinicians in their efforts to make the most appropriate therapeutic decisions while minimizing the potential gastrointestinal risks associated with the use of these agents. Side effects such as dyspepsia do not provide adequate warning of gastrointestinal complications, because most complications occur without the presence of antecedent symptoms. Therefore, accurate risk assessment and the management of controllable risk factors are crucial to the safe administration of NSAIDs. This review focuses on the gastrointestinal effects of aspirin, acetaminophen, and other nonselective NSAIDs, and discusses those factors that are associated with increased risk for adverse gastrointestinal events in certain individuals.

Risk of upper gastrointestinal bleeding associated with use of low-dose aspirin

OBJECTIVE

Aspirin products are known to cause irritation and injury to the gastric mucosa. We examined the risk of hospitalization for upper gastrointestinal bleeding with use of low-dose aspirin.

METHODS

This was a cohort study based on record linkage between a population-based prescription database and a hospital discharge registry in North Jutland County, Denmark, from January 1, 1991, to December 31, 1995. Incidence rates of upper gastrointestinal bleeding in 27,694 users of low-dose aspirin were compared with the incidence rates in the general population in the county.

RESULTS

A total of 207 exclusive users of low-dose aspirin experienced a first episode of upper gastrointestinal bleeding with admission to the hospital during the study period. The standardized incidence rate ratio was 2.6 (95% confidence interval, 2.2-2.9), 2.3 in women and 2.8 in men. The standardized incidence rate ratio for combined use of low-dose aspirin and other nonsteroidal anti-inflammatory drugs was 5.6 (95% confidence interval, 4.4-7.0). The risk was similar among users of noncoated low-dose aspirin (standardized incidence rate ratio, 2.6; 95% confidence interval, 1.8-3.5) and coated low-dose aspirin (standardized incidence rate ratio, 2.6; 95% confidence interval, 2.2-3.0).

CONCLUSIONS

Use of low-dose aspirin was associated with an increased risk of upper gastrointestinal bleeding, with still higher risks when combined with other nonsteroidal anti-inflammatory drugs. Enteric coating did not seem to reduce the risk. The findings from this observational study raise the possibility that prophylactic use of low-dose aspirin may convey an increased risk of gastrointestinal bleeding, which may offset some of its benefits.

Prevention of non-steroidal anti-inflammatory drug-induced gastrointestinal mucosal injury: risk factors for serious complications

BACKGROUND

1-2% of all patients under non-steroidal anti-inflammatory drug therapy are exposed to serious upper gastrointestinal complications. The policy of prevention of non-steroidal anti-inflammatory drug-induced gastrointestinal mucosal injury by using misoprostol or suppressing acid secretion is still a matter of debate.

AIMS

To discuss the effectiveness of prophylaxis of a gastrointestinal complication during non-steroidal anti-inflammatory drug treatment, according to the number and relevance of risk factors.

PATIENTS

A total of 8.843 patients with rheumatoid arthritis, admitted to the widest prospective multicentre mega-trial, on 6-month complication prevention of non-steroidal anti-inflammatory drug-induced ulcers.

METHODS

The results are presented in terms of the number of patients to be treated (number needed to treat) in order to prevent one serious upper gastrointestinal complication, and corrected for the number of patients, that receiving the prophylaxis therapy, would lead to one additional withdrawal (number needed to harm).

RESULTS

The base-line risk for a complication strongly depended on the number and relevance of risk factors: history of peptic ulcer disease, of gastrointestinal bleeding, of cardiovascular disease, and age. In the general study population, the relative risk reduction of gastrointestinal complications with misoprostol was 40%: thus the number needed to treat to prevent 1 event was 250 in the experimental period (6 months) or 125 when normalized at one-year treatment (1 year number needed to treat]. When considering the prophylaxis gain in intermediate (risk 1-2%) or high risk subjects (patients with a probability of an event over 2%, for the presence of 1 important risk factor or multiple factors), the 1-year number needed to treat rapidly drops from about 100 to about 17. The number needed to harm for one withdrawal was 18. The number needed to treat corrected for withdrawals in order to avoid major complications rises from 125 to 132 in the general population of non-steroidal anti-inflammatory drug users; from 102 to 105 in subjects at intermediate risk, such as patients with history of cardiovascular disease; in the groups at high risk, from 26 to 27 (patients with history of peptic ulcer disease), and from 16 to 17 (patients with history of peptic ulcer disease, cardiovascular disease and aged over 65 years).

CONCLUSIONS

Patients at intermediate and high risk for complications from non-steroidal anti-inflammatory drug-induced ulcers should be considered for prophylaxis. In this group of patients, misoprostol prevention of severe complications is effective, and its clinical relevance similar to that of other preventive measures in medical practice.

Comparative safety evaluation of non-narcotic analgesics

Both spontaneous reports and single outcome studies may distort the overall safety evaluation of drugs. We identified epidemiologic studies, published from January 1970 to December 1995, that investigated the association of serious adverse effects with aspirin, diclofenac, acetaminophen, and dipyrone to determine and compare the excess mortality associated with short-term drug use. The estimated excess mortality due to community-acquired agranulocytosis, aplastic anemia, anaphylaxis, and serious upper gastrointestinal complications was 185 per 100 million for aspirin, 592 per 100 million for diclofenac, 20 per 100 million for acetaminophen, and 25 per 100 million for dipyrone. The estimates were largely influenced by the excess mortality associated with upper gastrointestinal complications. A relative risk estimate of 300 or more for the association of dipyrone with agranulocytosis would have been necessary for the excess mortality of dipyrone to be comparable to that of aspirin or diclofenac. Based on published epidemiologic evidence used to determine the excess mortality associated with short-term use of these four non-narcotic analgesics, the current regulatory ranking of the drugs appears inappropriate.

[Risk of ulcer and its prophylaxis in therapy with non-steroidal antirheumatic drugs]

Nonsteroidal antiinflammatory drugs (NSAIDs) are among the most frequently prescribed drugs in western countries. The high incidence of adverse gastrointestinal effects which are potentially life-threatening require steps for prevention. The use of NSAIDs should be restricted to patients with inflammatory rheumatic diseases. If NSAIDs are indicated it is important to identify patients who are at high risk to develop serious gastrointestinal side effects. These patients should receive Misoprostol at a dose of 2 to 3 x 200 micrograms per day. Up to date Misoprostol is the only drug with proven efficacy with respect to the prevention of gastroduodenal ulcer and its complications. NSAIDs inhibit the key enzyme of prostaglandin synthesis, the cyclooxygenase. Recently published data show that 2 isoenzymes of the cyclooxygenase exists. Cyclooxygenase-1 is primarily involved in the maintenance of organ function whereas cyclooxygenase-2 is expressed in inflamed tissue. Specific cyclooxygease-2 inhibitors have been developed. Clinical trials have to prove if the concept of a selective cyclooxygenase-2 inhibition with high antiinflammatory potency but lack of gastrointestinal side effects holds true in humans.

Meta-analysis of risk factors for peptic ulcer. Nonsteroidal antiinflammatory drugs, Helicobacter pylori, and smoking

Attributable risk models describe the role of three risk factors for peptic ulcer and related serious upper gastrointestinal (GI) events. The factors-nonsteroidal antiinflammatory drugs (NSAIDs), Helicobacter pylori, and cigarette smoking-have been identified as major risk factors for peptic ulcer in numerous clinical and epidemiologic studies. Overall risk ratios for each risk factor were based on meta-analyses of English-language studies of risk for peptic ulcer-related GI events. Exposure estimates for factors used data from North American populations. Summary risk and exposure values were computed for the general population, males and females separately, and the elderly. Hypothetical models of multiple factor attributable risks were developed using population attributable risk percent calculated from these summary values. General population attributable risk percent were as follows: 24%, NSAIDs; 48%, H. pylori; and 23%, cigarette smoking. Based on these numbers, the "no interaction" attributable risk model estimates that 95% of total peptic ulcer related risk is attributable to these factors in the general population. The "interaction" model attributes 89% of cases to these risk factors: 24%, NSAIDs alone; 31%, H. pylori alone; 34%, H. pylori/smoking combined. Between 89% and 95% of peptic ulcer-related serious upper GI events may be attributed to NSAID use, H. pylori infection, and cigarette smoking.

Excess costs from gastrointestinal disease associated with nonsteroidal anti-inflammatory drugs

OBJECTIVE

To quantify medical care costs for the diagnosis and treatment of gastrointestinal disorders attributable to use of nonsteroidal anti-inflammatory drugs (NSAIDs) other than aspirin in elderly persons.

DESIGN AND SETTING

Retrospective cohort study of 75,350 Tennessee Medicaid enrollees at least 65 years of age.

MEASUREMENTS

The cohort was classified by baseline NSAID use as nonusers (no use preceding 1988), occasional users (< 75% of days) or regular users (> or = 75% of days). For the follow-up year (1989), we calculated annual rates of utilization of and Medicare/Medicaid payments for: medical care for NSAID-associated gastrointestinal disorders; hospitalizations/emergency department visits for peptic ulcers, gastritis/duodenitis, and gastrointestinal bleeding; outpatient upper and lower gastrointestinal tract radiologic and endoscopic examinations; and histamine2 (H2)-receptor antagonist, sucralfate, and antacid prescriptions. Rates were adjusted for demographic characteristics and baseline health care utilization.

RESULTS

Among nonusers of NSAIDs, the adjusted mean annual payment for all types of medical care for study gastrointestinal disorders was $134. This increased to $180 among occasional users, an excess of $46 (p < .001); and to $244 among regular users, an excess of $111 (p < .001, comparison with both nonusers and occasional users). Cohort members with any baseline year NSAID use had an adjusted mean annual payment of $191, $57 (p < .001) higher than that for nonusers. In both users and nonusers of NSAIDs, medications and inpatient care accounted for the largest component of costs. Among regular NSAID users, excess payments increased with baseline NSAID dose: $56, $120, and $157 for less than 1, 1 to 2, and more than 2 standard units per day, respectively (p < .01, linear trend).

CONCLUSIONS

Nonsteroidal anti-inflammatory drug (NSAID) use in elderly patients was associated with substantial excess costs and utilization of medical care for gastrointestinal disorders.

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

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

Reversible prolonged skin bleeding time in acute gastrointestinal bleeding presumed due to NSAIDs

The purpose of this research was to look for a possible mechanism whereby NSAIDs, and particularly ASA, might cause gastrointestinal bleeding. A total of 34 hospitalized GI bleeders and 29 age- and sex-matched controls were studied. Skin bleeding time (SBT) was measured within 6 h of coming to hospital and before any blood products were given. All patients and controls were questioned regarding current NSAID use. This history was supplemented by estimation of serum salicylate and of platelet cyclooxygenase activity to detect unreported current aspirin (ASA) use. Various aspects of platelet function were also tested by lumiaggregation in 28 controls and, after recovery, in 27 of the bleeders. Of 34 bleeders, 26 bled from the upper GI tract, (13 from peptic ulcer) and eight from the lower GI tract, 30 (88%) had a current intake of NSAIDs and of these 22 (73%) used ASA, some in combination with other NSAIDs, whereas 12 of 29 controls were using NSAID's, 11 of which were ASA. SBT in the bleeders was 9.0 +/- 1.02 min versus 4.8 +/- 0.42 min in the controls (p < 0.001). SBT measured 6.6 days later in 28 bleeders was 4.7 +/- 0.22 min (p < 0.0006), and of those tested after recovery all but one had fallen to 6.5 min or less. None had any residual constitutional platelet abnormalities as tested by lumiaggregation. By logistic regression, NSAID intake was strongly associated with prolonged SBT to > 6 min (odds ratio [OR], 16.7; p < 0.0002), whereas NSAID intake (OR 14.6; p < 0.0003) and SBT > 6 min (OR 1.8; p < 0.005) contributed to a bleeding outcome. Almost 90% of GI bleeders had recently consumed NSAIDs, mostly ASA, on an average 15 h before onset of bleeding. Although most of the nonbleeders who had used NSAIDs did not have a prolonged SBT, most of the bleeders who used NSAIDs had an abnormal elevation of SBT, suggesting a possible mechanism for GI bleeding. Retesting approximately 7 days after recovery from bleeding showed normalization of the SBT, indicating that the defect was transient and spontaneously reversible.

Aspirin or acetaminophen? A comparison from data collected by the Spanish Drug Monitoring System

To characterize and compare the toxicity profiles of aspirin and acetaminophen when used by large populations, all records of adverse drug reactions to these drugs reported to the Spanish Drug Monitoring System from 1982 to 1991 were analyzed. According to these data, aspirin-induced reactions were more serious than those reactions to acetaminophen; the severity of all the reactions in both cases was associated with time of exposure and with the accumulated dose administered. For GI reactions to aspirin no association was found between severity and time of exposure or dose, although an association with age was found. There were no differences between the proportions of deaths, malformations, and renal damage recorded for either of the two groups. Proportions of hematological and hepatic disturbances were greater with acetaminophen. Adverse drug reaction data for aspirin and acetaminophen from spontaneous reporting seem to be consistent with data coming from observational studies.

Diclofenac/misoprostol. A review of its pharmacology and therapeutic efficacy in painful inflammatory conditions

Diclofenac is a well established nonsteroidal anti-inflammatory drug (NSAID) used in the treatment of a variety of painful inflammatory conditions. Although generally well tolerated, diclofenac, like other NSAIDs, is associated with gastrointestinal adverse effects which infrequently can be serious and/or life-threatening. Misoprostol, a prostaglandin E1 analogue, reduces the incidence of NSAID related ulcers, both gastric and duodenal. The lack of conclusive pharmacoeconomic data for misoprostol and the widespread use of NSAIDs makes routine administration of misoprostol difficult to justify for all NSAID users. However, it appears to be an economically warranted approach in the elderly, who are at particularly high risk for NSAID-related gastrointestinal complications. The fixed combination of diclofenac 50mg and misoprostol 200 micrograms administered 2 to 3 times daily for 4 to 12 weeks has shown equivalent therapeutic efficacy to diclofenac (alone or combined with placebo), piroxicam and naproxen, and was slightly more effective than ibuprofen in clinical studies in patients with a variety of painful inflammatory conditions. No significant differences in therapeutic efficacy were noted between elderly (aged > or = 65 years) and younger patients in these studies. Gastrointestinal adverse events are common with diclofenac and misoprostol, administered alone or in combination. Diarrhoea (presumably attributable to the misoprostol component) appears to be more frequent in diclofenac/misoprostol recipients than in those receiving diclofenac alone or combined with placebo. However, diclofenac/misoprostol recipients had significantly fewer gastroduodenal ulcers at the end of treatment relative to patients receiving comparators in clinical trials. In addition, the types and incidences of adverse events are similar in elderly and younger patients. Routine ulcer prophylaxis with misoprostol in all NSAID users is not warranted from a pharmacoeconomic viewpoint. In common with other fixed combination products, dosage flexibility is somewhat compromised with diclofenac/misoprostol. However, once drug dosages are determined in the individual patient, the fixed combination of diclofenac and misoprostol offers the potential for increased patient convenience and possibly patient compliance, and lower drug acquisition costs than those of the individual drugs used together. Thus, it should be considered a useful treatment option in appropriately selected patients with a high risk for serious NSAID-related gastrointestinal complications who require NSAID therapy.

From peptic ulcer disease to NSAID gastropathy. An evolving nosology

Nonsteroidal anti-inflammatory drug (NSAID)-induced gastropathy is an important clinical entity, most commonly encountered in elderly female patients. The expanding use of NSAIDs in the elderly population has led to an increased incidence of NSAID-induced gastropathy. The risk of gastric bleeding in these patients is 7-fold higher than in the younger population. Long term NSAID therapy in the elderly is apparently associated with failure of normal gastric mucosal adaptation. Silent unidentified gastric lesions are likely to be common with long term NSAID therapy, as symptomatology does not parallel pathological progression. This gastropathy, in contrast to peptic ulcer disease, is responsive to prostaglandins and other cytoprotective agents. A new generation of prostaglandin-sparing NSAIDs (e.g. nabumetone), in addition to the older nonacetylated salicylates, may represent less gastrotoxic alternatives. Therefore, these agents may substantially reduce the risk of NSAID-induced gastropathy. The debate continues as to whether to use NSAIDs, and under which circumstances. More importantly, the cost-benefit implications and justification for concomitant therapy with gastroprotective agents cloud the picture. Currently, there is a definite consensus that NSAIDs should not be casually used on a chronic basis, especially in patients at risk for serious gastropathy complications. In all cases, where possible, gastric prostaglandin-sparing NSAIDs or nonacetylated salicylates should be used in lowest effective dosages. In special circumstances, gastroprotective co-therapy can be considered. NSAID therapy probably should not be used or continued in elderly patients with a history of bleeding ulcers or recent major gastric ulcer activity.

Prophylactic aspirin and risk of peptic ulcer bleeding

OBJECTIVE

To determine the risks of hospitalisation for bleeding peptic ulcer with the current prophylactic aspirin regimens of 300 mg daily or less.

DESIGN

A case-control study with hospital and community controls.

SETTING

Hospitals in Glasgow, Newcastle, Nottingham, Oxford, and Portsmouth.

SUBJECTS

1121 patients with gastric or duodenal ulcer bleeding matched with hospital and community controls.

RESULTS

144 (12.8%) cases had been regular users of aspirin (taken at least five days a week for at least the previous month) compared with 101 (9.0%) hospital and 77 (7.8%) community controls. Odds ratios were raised for all doses of aspirin taken, whether compared with hospital or community controls (compared with combined controls: 75 mg, 2.3 (95% confidence interval 1.2 to 4.4); 150 mg, 3.2 (1.7 to 6.5); 300 mg, 3.9 (2.5 to 6.3)). Results were not explained by confounding influences of age, sex, prior ulcer history or dyspepsia, or concurrent non-aspirin non-steroidal anti-inflammatory drug use. Risks seemed particularly high in patients who took non-aspirin non-steroidal anti-inflammatory drugs concurrently.

CONCLUSION

No conventionally used prophylactic aspirin regimen seems free of the risk of peptic ulcer complications.

Evidence of the depletion of susceptibles effect in non-experimental pharmacoepidemiologic research

Past experience with a drug may modify the risk of adverse event associated with current use of this drug. This effect was investigated empirically with a study on non-steroidal anti-inflammatory drugs (NSAIDs)-gastropathy. A hospital-based case-control study was conducted with 244 cases of upper gastrointestinal bleeding (UGIB) age 68 and over and 615 matched controls. Data on all medications dispensed to the study patients during the 3 years preceding admission were obtained from the Quebec universal prescription program automated database. Recent use (within 30 days prior to admission) of non-aspirin NSAIDs increased the risk of UGIB. The estimate of relative risk (RR) was 3.4 (CI, 2.1-5.5). Use of NSAIDs in the previous 3 years was associated with a lower risk of UGIB; the estimate of RR was 0.7 (CI, 0.4-1.0). The estimate of RR for first-time users was 22.7 (2.8-200.0) vs 3.0 (1.9-4.7) for those who had used the drugs at least once in the past 3 years. These results provide empirical evidence of a depletion of susceptibles effect whereby patients who remain on the drugs are those who can tolerate them while those who are susceptible select themselves out of the population at risk. Thus, past use should be considered as a potential risk modifier in non-experimental risk assessment of events associated with drug use.

Nabumetone: a clinical appraisal

Nonsteroidal antiinflammatory drugs (NSAIDs) have long been used as therapy for arthritis patients. However, in some patients these drugs can cause gastrointestinal hemorrhage, perforation, or ulcer through direct topical effects, enterohepatic recirculation, and systemic effects. In an effort to address this problem, new NSAIDs have been developed. Nabumetone, which belongs to a new class of NSAID, is a nonacidic agent that has been associated with a low incidence of peptic ulcer. This article examines available clinical data on nabumetone, including studies on gastrointestinal safety and effectiveness in osteoarthritis and rheumatoid arthritis patients, and data that may provide an explanation for nabumetone's low incidence of ulceration.

Epidemiology of gastrointestinal damage associated with nonsteroidal anti-inflammatory drugs

Nonsteroidal anti-inflammatory drugs (NSAIDs) are associated with significant upper gastrointestinal (GI) toxicity, with a relative risk of approximately 3. This is supported by evidence drawn from randomised controlled trials [of aspirin (acetylsalicylic acid)], cohort studies and case-control studies. The risk is increased with higher doses of medication, shorter treatment duration and concomitant corticosteroid use. Elderly patients and those with a history of GI illness are also at increased risk. Ibuprofen may be associated with a lower, and piroxicam with a higher, risk of complications. There are only preliminary data regarding an association between NSAIDs and small and large intestinal complications. Therapeutic alternatives which may confer a lower risk of significant GI toxicity include enteric-coated preparations, non-acetylated salicylates, and NSAIDs taken in conjunction with misoprostol. Epidemiological data regarding these alternatives are sparse.

Gastric tolerability of nimesulide. A double-blind comparison of 2 oral dosage regimens and placebo

This double-blind parallel-group study aimed to evaluate, by endoscopic examination, the reaction of the gastric mucosa to 7-day oral administration of nimesulide 100 or 200mg twice daily. Placebo was administered as a reference compound. 30 dyspeptic patients, randomly allocated to 1 of the 3 treatment groups, completed the study. On completion of treatment, 1 patient in each nimesulide dosage group and 2 in the control group showed evidence of gastric injury: 1 patient with slight hyperaemic gastropathy at baseline developed superficial ulcerations after treatment with nimesulide 100mg, and 1 patient with a history of gastric ulcer developed a congested corpus mucosa with several erosions and ulcerations after treatment with nimesulide 200mg; in the placebo group, 1 patient developed hyperaemic antropathy and another patient developed several petechiae and microerosions. The incidence of adverse effects was comparable in all groups and treatment was not associated with any significant modification of the considered haematological and haematochemical parameters.

Non-steroid anti-inflammatory drug associated ulcer: epidemiology, causation and treatment

Epidemiological evidence consistently indicates that aspirin or non-aspirin non-steroidal anti-inflammatory drug use is associated with the occurrence of gastric ulceration, gastric and ulcer bleeding, and ulcer death. Evidence on duodenal ulcer occurrence conflicts, possibly because of differences in study populations. A wide range of mechanisms could explain the occurrence of non steroidal-induced damage. These include inhibition of bicarbonate secretion, effects on mucus formation, and vascular actions. Not all effects are dependent on cyclo-oxygenase inhibition. Short-term studies in humans provide indications of likely therapeutic effects, but cannot demonstrate clinical efficiency. Although anti-secretory drugs and prostaglandins can protect patients against the development of duodenal or gastric ulcers, but not both, there is no clinical evidence which bears upon the critical issue of protection against complications.

Aspirin potentiates prestimulated acid secretion and mobilizes intracellular calcium in rabbit parietal cells

The effects of aspirin on gastric acid secretion were studied in isolated rabbit parietal cells (PC). Aspirin (10(-5) M) potentiated histamine-, dibutyryl cyclic AMP (dbcAMP)-, forskolin- and 3-isobutyl-1-methylxanthine-stimulated acid secretion without affecting basal acid secretion. Augmentation of secretagogue-stimulated acid secretion by aspirin was dependent on calcium (Ca2+) since potentiation was blocked by removal of extracellular Ca2+ ([Ca2+]o) or addition of the calcium antagonist lanthanum chloride. Using the Ca2+ probe fura-2, aspirin (10(-6) - 2 X 10(-5) M) rapidly increased intracellular free Ca2+ concentration ([Ca2+]i) in a dose-dependent manner. The source of released Ca2+ was intracellular as demonstrated by depletion of intracellular Ca2+ and [Ca2+]o with EGTA washing. Aspirin did not affect several other signal transduction sites involved in stimulus-secretion coupling, including the H2 receptor, intracellular cyclic AMP (cAMP), inositol 1,4,5, triphosphate (IP3) and H+,K(+)-ATPase. Aspirin decreased PC prostaglandin E2 (PGE2) content by 98%. Exogenous dimethyl PGE2 (dmPGE2) inhibited both histamine-stimulated acid secretion and its enhancement by aspirin. In contrast, dmPGE2 abolished aspirin-induced potentiation of dbcAMP-stimulated acid secretion by augmenting the dbcAMP-stimulated response. These results indicate that aspirin acts at a site beyond the adenylate cyclase/cAMP system and before the proton pump, presumably by releasing Ca2+ from an IP3-independent intracellular storage pool and by inhibiting PGE2 generation.

Gastrointestinal ulcerations induced by anti-inflammatory drugs in rats. Physicochemical and biochemical factors involved

Aspirin, diclofenac, diflunisal, ibuprofen and indomethacin were given orally or intravenously to fasted or fed rats. The resulting gastric and intestinal damage was assessed using standard methods. The same drugs were administered to rats with biliary fistulas, and the fraction of drug excreted in bile was quantified using HPLC methods. We found that gastric damage occurred only in the fasted animals and was found to be dose-dependent and related to the amount (r = 0.871) and solubility (r = 0.909) of the individual drug. As far as acute gastric toxicity is concerned, neither the potency of a drug as an inhibitor of cyclo-oxygenase nor the fraction of unchanged or conjugated agent excreted in bile appeared to be relevant. Secondly, ulcerations of the small intestine occurred in fed animals only. The degree of damage was related to the amount of unchanged or conjugated drug excreted in bile and cyclo-oxygenase inhibitory potency (r = 0.873). The administered dose (within the range investigated) and drug solubility appeared not to contribute to intestinal toxicity. It is concluded that, in the rat, acute gastric and intestinal toxicity of non-steroidal anti-inflammatory drugs are due to different mechanisms. Whereas gastric toxicity is strongly influenced by the amount of drug dissolved under the pH conditions in the stomach, intestinal toxicity appears to depend on biliary excretion and enterohepatic circulation of a drug as well as on its potency as an inhibitor of prostaglandin synthesis.

Biliary elimination of non-steroidal anti-inflammatory drugs in patients

In view of evidence in animals that enterohepatic recirculation of non-steroidal anti-inflammatory drugs contributes to small intestinal mucosal damage we have investigated the extent of biliary elimination of three nonsteroidals. Ibuprofen (n = 3), diclofenac (n = 2) and indomethacin (n = 3) were given to six patients with a percutaneous transhepatic cholangiodrainage placed in the bile duct system. One patient received all three drugs. The mean biliary elimination of ibuprofen was 0.82% of the given dose compared with 50.41% urinary excretion. When diclofenac or indomethacin was administered 4.62% and 6.40% of the dose were found in bile, whereas 34.73% and 32.22% (means) were recovered from urine, respectively. The mean percentage eliminated in bile as unchanged drug and active phase II metabolites was 0.15% for ibuprofen, 1.09% for diclofenac and 5.02% for indomethacin.