NEW YORK (Reuters Health) – A high loading dose of clopidogrel — 600 mg — appears to be unnecessary in Asian patients with ST-segment elevation myocardial infarction (STEMI) who are undergoing primary percutaneous intervention (PCI). The standard 300-mg dose is just as safe and effective, a South Korean team reports.

Dr. Dong Joo Oh, with the Korea University and Guro Hospital in Seoul, and colleagues point out in the January 18 online issue of the American Heart Journal that several studies have shown that a 600-mg loading dose of clopidogrel produces greater platelet inhibition than a 300-mg loading dose in patients undergoing PCI.

However most of those studies have been conducted in Western populations. “Because of relatively smaller body weight, different degree of platelet aggregation, and possible ethnic differences in clopidogrel response, the optimal clopidogrel loading dose in Asian patients may not be same as that in Western people,” the authors explain.

To investigate, the team compared bleeding, vascular complications, and outcomes up to 12 months in 2,664 Korean patients with STEMI undergoing primary PCI who were treated with either a 300-mg or a 600-mg loading dose of clopidogrel.

“There were no differences in in-hospital and 1-month cardiac death, noncardiac death, recurrent MI, repeated PCI, total MACEs (major adverse cardiac events), and bleeding complications between the 300- and the 600-mg loading dose groups,” the investigators found.

Also at 12 months there was no between-group difference in cumulative clinical outcomes. Furthermore, these results held true in a propensity score-matched analysis.

“In conclusion,” Dr. Oh and colleagues write, “we suggest that a standard loading dose of clopidogrel (300 mg) would be enough for Asian STEMI patients undergoing primary PCI when considering the safety and clinical efficacy as well as the cost-effectiveness.”

Reference:
Standard versus high loading doses of clopidogrel in Asian ST-segment elevation myocardial infarction patients undergoing percutaneous coronary intervention: Insights from the Korea Acute Myocardial Infarction Registry
Am Heart J 2010.