Nitric oxide-releasing NSAIDs: GI-safe antithrombotics.

Aspirin is increasingly being used for long-term prophylaxis of myocardial infarction and stroke, but its use is limited by toxicity in the gastrointestinal tract. Even very low doses of aspirin can markedly increase the risk of gastrointestinal bleeding and ulceration. While proven effective in prophylaxis of stroke and myocardial infarction, the efficacy of aspirin is limited. Addition of a nitric oxide-releasing moiety to several non-steroidal anti-inflammatory drugs results in a profound reduction in their toxicity in the gastrointestinal tract and kidney. A similar derivatization of aspirin has recently been shown to result in a more potent, gastrointestinal-sparing antithrombotic drug. Two such compounds (NCX-4215 and NCX-4016; NicOx SA) have undergone detailed evaluation thus far. In each case, the NO-aspirin has shown improved anti-aggregatory activity while not inducing detectable gastric damage. The compounds have also been shown to exert protective effects in the gastrointestinal tract exposed to other injurious agents. The NO-aspirin derivatives significantly inhibit leukocyte adherence to the vascular endothelium, which may contribute to their anti-thrombotic activity. NO-releasing derivatives of aspirin and naproxen also exhibit beneficial effects in experimental hypertension, which would also contribute to improved anti-thrombotic activity. NO-releasing derivatives of NSAIDs offer great potential as gastrointestinal-sparing anti-thrombotic drugs.