Concomitant use of buffered and enteric-coated low-dose aspirin products and antisecretory drugs

Buffered and enteric-coated formulations of low-dose aspirin therapy are although expected to avoid gastrointestinal complications, there are reports that these modified products are associated with such complications. One available option for preventing aspirin-induced gastrointestinal complications is the simultaneous use of the agents that inhibit acid secretion such as H(2)-receptor antagonists and proton pump inhibitors. We compared the frequency of prescriptions for antisecretory drugs between users of either buffered or enteric-coated low-dose aspirin.

Monthly prescriptions at the National Cardiovascular Center for aspirin products and antisecretory drugs were counted from January 1998 to December 2002. Counting was based on information from a prescription database file compiled from a computerized order entry system. Time-series analyses were performed to determine changes in the frequency of prescriptions for low-dose aspirin products and antisecretory drugs. In addition, the frequency of prescriptions for antisecretory drugs was compared in individuals using either buffered or enteric-coated low-dose aspirin.

A significant reduction in the frequency of prescriptions for H(2)-receptor antagonists was observed during 2001 in users of enteric-coated low-dose aspirin compared with users of buffered low-dose aspirin users. In contrast, we observed a significant increase in the frequency of prescriptions for H(2)-receptor antagonists in users of enteric-coated low-dose aspirin during 2002. This change in prescribing H(2)-receptor antagonists in users of enteric-coated low-dose aspirin began in the latter half of 2001. Proton pump inhibitors accounted for 0.31% of prescriptions in users of buffered low-dose aspirin and 0.47% in users of enteric-coated low-dose aspirin, with this difference being statistically significant.

The findings of the present study do not support the notion that enteric-coated low-dose aspirin reduces the risk of gastrointestinal complications and is safer than buffered low-dose aspirin products. However the usual caution about making inferences from observational retrospective data is appropriate.