Are there any published data regarding the need to stop aspirin or clopidogrel prior to undergoing colonoscopy for positive fecal occult blood or routine screening for history of polyps?
—Nagaraju Choragudi, MD, Iron Mountain, Mich.

I could find no published studies on the safety of endoscopic procedures in patients taking antiplatelet medications, such as clopidogrel. However, the Standards of Practice Committee of the American Society for Gastrointestinal Endoscopy has published a guideline on the use of non-aspirin antiplatelet agents prior to endoscopic procedures based on the pharmacology and known clinical effects of these agents (Gastrointest Endosc. 2005;61:189-194). They recommend that for patients undergoing low-risk endoscopic procedures (such as colonoscopy with or without biopsy), no adjustments in the antiplatelet regimen be made. However, for higher-risk procedures (such as polypectomy), they suggest considering stopping the medication 7-10 days before the procedure and restarting it the following day but also note that the need to stop the medication has not been conclusively determined. In contrast, aspirin and other nonsteroidal anti-inflammatory drugs may be continued in patients undergoing endoscopy in the absence of a pre-existing bleeding disorder (Gastrointest Endosc. 2002;55:775-779).
—Daniel G. Tobin, MD (115-18)