Antithrombotic effect of different acetylsalicylic acid drug formulations: is there a difference?

To date, a sufficient volume of clinical studies has been accumulated that have demonstrated a reduced antiplatelet effect of enteric-coated (EC) lowdose acetylsalicylic acid (ASA). Delayed and incomplete absorption from the intestinal alkaline medium, which significantly reduces the bioavailability of drug, is considered the main reason for laboratory aspirin resistance (pseudoresistance) to EC ASA. This phenomenon is of particular importance for patients with acute coronary syndrome, when a quick effect is required, as well as for patients with diabetes and obesity due to additional causes of increased platelet activity, on the one hand, and reduced bioavailability of ASA, on the other. Given the issue of efficacy, the dubious gastroprotective effect and the more pronounced damaging effect on the mucous membrane of small intestine, the use of EC ASA should be avoided, especially in patients with a multifactorial risk of insufficient response to therapy. A good alternative is buffered ASA, which quickly dissolves and is partially absorbed directly in the stomach, having antiplatelet activity comparable to simple ASA and a similar aspirin resistance, is associated with a lower risk of aspirin-induced enteropathy in comparison with ES ASA. In addition, according to a number of small studies and retrospective analyzes, buffered ASA is less likely to cause damage to gastric mucosa compared to EC ASA.