Comparison of enteric-coated aspirin and uncoated aspirin effect on bleeding time

Aspirin therapy is an essential part of the drug regimen for patients with acute myocardial infarction (MI), unstable angina, or after coronary angiop lasty and coronary stenting. Recognizing this importance, this study sought to compare the bleeding time in two groups of 10 normal volunteers 4 hr af ter ingestion of either an enteric-coated aspirin or an uncoated aspirin, a ssuming that a difference between the two groups could be clinically signif icant. Defining less than or equal to 8 min as normal, 80% of the uncoated group developed abnormal bleeding times, compared to 10% of the enteric-coa ted group (P < 0.01). The study demonstrates a significant difference betwe en the two types of aspirin preparations on bleeding times in normal indivi duals. This strongly suggests that some enteric-coated aspirin preparations may not be as effective as uncoated aspirin in acutely decreasing platelet aggregation. Therefore, uncoated aspirin is recommended in the setting of acute MI, unstable angina, or after percutaneous transluminal coronary angi oplasty. Cathet, Cardiovasc. Diagn. 45:396-399, 1998. (C) 1998 Wiley-Liss, Inc.