Salicylates revisited. Are they still the hallmark of anti-inflammatory therapy?

Nonsteroidal anti-inflammatory drug gastropathy: new avenues for safety

Chronic oral or systemic nonselective nonsteroidal anti-inflammatory drug (NSAID) therapy, ubiquitously used by physicians to treat osteoarthritis-associated pain, is associated with a wide range of symptomatic adverse events, the most frequent and serious of which is gastropathy. Although cardiovascular and renal problems are a very real concern, they are significantly less frequent. These complications can be life-threatening in at-risk populations such as older adults, who are common users of long-term oral systemic NSAID therapy. Topical NSAID formulations deliver effective doses of analgesics directly to the affected joints, thereby limiting systemic exposure and potentially the risk of systemic adverse events, such as gastropathy and serious cardiovascular events. There are currently two topical NSAIDs approved by the US Food and Drug Administration for osteoarthritis-associated pain, as well as for the signs and symptoms of osteoarthritis. This review discusses the relative safety, and the gastrointestinal, cardiovascular, and renal risks of chronic oral or systemic NSAID therapy and topical NSAID formulations in patients with osteoarthritis.

Epidemiology of adverse drug reactions in the elderly by drug class

As the growth of the elderly population continues, the burden on the health care system and society will also increase. Since chronic diseases such as hypertension, coronary artery disease, arthritis, stroke, cancer and diabetes mellitus are more prevalent with age, the number of people with multiple chronic diseases will also increase. These patients are likely to be treated for some or all of their conditions with drug therapies. When used appropriately, drugs may be the single most important intervention in the care of an older patient, but when used inappropriately they no longer provide therapeutic benefit, and they may even endanger the health of an older patient by causing an adverse drug reaction (ADR). Factors believed to be responsible for increased adverse reactions in elderly patients are polypharmacy (including prescription and over-the-counter medications), increased drug-drug interaction, pharmacokinetic changes, pharmacodynamic changes, the pathology of aging and compliance. The exact role that age plays in ADRs is not clear. This is in part because few older patients are included in the large randomised trials, and so much of the information used to ascertain the age-associated risks of drugs comes from observational studies. Although the interactions of aging, concurrent comorbidities and polypharmacy are known, older patients do appear to be at increased risk. Improvements in the management of drug therapies of older patients can lead to improvements in their overall health, functioning and safety, as well as providing potential benefits to society by ameliorating some of the burden of their health care.

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.

Adverse Gastrointestinal Effects of Nonsteroidal Anti-Inflammatory Drugs

There are a substantial number of adverse reactions attributable to nonsteroidal anti-inflammatory drug (NSAID) therapy, particularly of the gastrointestinal (GI) tract. The stomach is most commonly affected, although injury may occur from esophagus to colon. The incidence of developing serious GI toxicity seems to be three times as great in users compared with nonusers of NSAIDs. Age greater than 60 years, history of GI problems, previous corticosteroid use, and recency of NSAID use seem to increase the risk of toxicity. Short-term studies have found differences in ulceration or bleeding caused by various NSAIDs. However, there are insufficient long-term clinical trials involving adequate numbers of patients to demonstrate substantial advantages for any particular NSAID based on its toxicity profile. Prostaglandin inhibition seems to be one mechanism responsible for the GI toxicity of NSAIDs, but it is probably not the only mechanism. When serious GI bleeding occurs, the NSAID use must be stopped, although omeprazole and misoprostol have been used successfully to treat gastroduodenal ulcerations in patients while continuing NSAID therapy. Misoprostol and possibly omeprazole have effectively prevented GI ulceration associated with NSAID therapy, but questions remain regarding patient selection, length of therapy, and their utility in preventing serious GI bleeding. At this time, routine prophylaxis for patients receiving long-term NSAID therapy cannot be recommended.

Abnormal platelet hydrogen peroxide metabolism in aspirin hypersensitivity

The generation and degradation of hydrogen peroxide (H2O2) by platelets was investigated in aspirin hypersensitive and tolerant allergic subjects, and compared to that in general medical patients and healthy controls. H2O2 generation following triggering with anti-IgE, specific allergen, and with aspirin (ASA) and indomethacin was examined using a chemiluminescence assay. Platelet levels of the main intracellular enzyme responsible for H2O2 metabolism--glutathione peroxidase--were measured by a quantitative functional assay. H2O2 secretion could be triggered by anti-IgE in platelets from 15/29 ASA-tolerant atopics, and by relevant allergen in platelets passively sensitized with allergen-specific IgE. A similar response was observed following triggering with ASA, and with indomethacin, in platelets from 8/25 ASA-sensitive subjects. Mean platelet glutathione peroxidase activity was significantly lower in subjects with ASA-induced asthma, but not in subjects with non-asthmatic reactions to ASA, compared to all other groups. Within the ASA-sensitive group there was no correlation between low peroxidase activity and ASA-triggered chemiluminescence. Our findings emphasize the heterogeneity of ASA-intolerance syndromes and point to abnormal oxygen/peroxide metabolism as a common pathway underlying ASA-induced asthma.

New understandings of NSAID gastropathy

Non-steroidal anti-inflammatory drug (NSAID)-induced gastropathy is a serious public health problem. The United States Food and Drug Administration has recently proposed strong class labelling for NSAIDS, warning of the risk of ulceration, bleeding and perforation associated with their use. The adaptation of the gastric mucosa in response to NSAID intake in volunteers does not seem to occur to the same extent in rheumatic patients. In an ongoing study of patients with osteo- or rheumatoid arthritis, currently in its fourth year, nabumetone has been shown to be relatively gastric sparing when compared with naproxen. Nabumetone is at least as effective as naproxen. Long-term studies are important as treatment of arthritis may involve prolonged use of NSAIDs.