The American College of Cardiology (ACC), American Heart Association (AHA) and American College of Gastroenterology (ACG) have jointly said that there is no definitive evidence that the use of proton pump inhibitors (PPIs) will keep clopidogrel from working to prevent cardiac events.
The three groups said that PPIs’ impact on clopidogrel’s antiplatelet effect has not been studied in large numbers of patients.
Previously, the ACC/AHA recommended that the dual-antiplatelet therapy (aspirin plus a thienopyridine, such as clopidogrel) follow stent placement.
The associations said that neither of the studies presented at last week’s AHA Scientific Sessions provide “sufficient evidence to change clinical practice.” In the interest of patient safety, the AHA/ACC/ACG advised that patients who are currently taking the medications should not change their medication regimen unless advised by their healthcare provider.
The first study reviewed major adverse cardiac events (hospitalization for stroke, MI, angina or bypass surgery) over one year in patients prescribed clopidogrel after stent placement. The study group included 14,383 patients in the Medco Integrated Database, who were at least 80 percent compliant with refilling their medication. Patients who took clopidogrel alone were compared with those taking clopidogrel and PPIs. The study found that patients receiving both medications had significantly more major cardiovascular events in a year than patients taking clopidogrel alone.
However, the associations said that there were several significant limitations to this type of study: the database did not include information about participants’ use of over-the-counter drugs and could not account for other cardiovascular risk factors, such as family history, smoking status, blood pressure levels and lipid values. The authors themselves concluded that further investigation should focus on prospective study of the interaction.
The second study, also presented Nov. 12, reported no adverse effect of combining a PPI with clopidogrel. CREDO previously found a benefit of one year versus one month of treatment with clopidogrel after coronary stenting. The sub-group analysis assessed the endpoint of death, MI or stroke in patients on clopidogrel or placebo with or without a PPI, and showed no adverse effect of combining a PPI with clopidogrel. Patients treated with a PPI were at higher baseline risk and had a worse outcome compared to those who were not, whether they were given placebo or clopidogrel.
The associations also noted that the ongoing COGENT-1 study should help answer some of these questions—the trial is randomizing patients with coronary artery disease to aspirin plus clopidogrel, in combination with 20 mg of the PPI, omeprazole, or placebo. They said that COGENT-1 should provide further evidence to help address these issues.