Clopidogrel, in combination with aspirin, is currently the recommended treatment for
secondary prevention of ischemic events in high-risk patients and for prevention of coronary
artery stent thrombosis. Patients receiving aspirin and clopidogrel are frequently treated
with proton pump inhibitors, such as omeprazole or pantoprazole, in order to prevent the risk
of gastrointestinal bleeding, accorded to guidelines. An interaction between proton pump
inhibitors and clopidogrel has been suggested, which may lead to a decrease of clopidogrel
effects. It remains unclear whether this interaction between PPIs and clopidogrel might be a
class effect or if this may be affected by timing regimen.
The objectives of this two-phase investigation are:
1. to compare clopidogrel platelet inhibitory effects when taken at the same time versus
separated at least 8 hours from omeprazole administration.
2. to compare clopidogrel-induced inhibitory effects when taken at the same time versus
staggered at least 8 hours from pantoprazole administration.