New insight into the mechanisms of gastroduodenal injury induced by nonsteroidal anti-inflammatory drugs: practical implications

Nonsteroidal anti-inflammatory drugs (NSAIDs), especially acetylsalicylic acid (ASA), are commonly used in the therapy of various diseases. However, the serious side effects of these drugs, such as bleedings, acute lesions, gastric ulcers, and even intestinal perforations, are widely recognized. NSAIDs inhibit cyclooxygenase (COX) activity resulting in the suppression of mucosal generation of gastroprotective prostaglandins (PGs) derived from a constitutive isoform, COX-1, as well as an inducible isoform, COX-2. COX-1-derived PGs are responsible for gastroprotection, while PGs generated via COX-2 activity also play an important role in gastroprotection and ulcer healing. Recently, a new class of NSAIDs has been developed by adding NO moiety to conventional NSAIDs. In contrast to native NSAIDs, their NO-releasing derivatives such as NO-ASA were found to exhibit lower gastric toxicity despite inhibiting both COX-1 and COX-2 activity in the gastric mucosa. Similar limited gastrointestinal toxicity and protective actions were observed with a new class of hydrogen sulfide (H2S)-releasing NSAIDs, such as H2S-releasing naproxen (ATB-346). Dual antiplatelet therapy with ASA and clopidogrel increases the risk of gastrointestinal bleeding in patients with acute coronary syndrome in whom concomitant treatment with a proton-pump inhibitor (PPI) was less effective owing to the interaction of clopidogrel and PPI with the same hepatic cytochrome P-450. In conclusion, new derivatives of NSAIDs releasing vasoactive gaseous mediators NO or H2S are associated with fewer gastrointestinal adverse effects, suggesting that, in the future, they may be used as a safer alternative in everyday clinical practice and antithrombotic therapy.