Is a high maintenance dose of clopidogrel suitable for overcoming clopidogrel resistance in patients?

Background: A double maintenance dose of clopidogrel at 150 mg daily has been suggested as an effective alternative treatment for patients who have clopidogrel resistance.

Objective: To determine if a double maintenance dose of clopidogrel can overcome the low drug response rate observed in patients who have clopidogrel resistance while on a 75 mg daily standard maintenance dose of clopidogrel.

Methods: A retrospective analysis was conducted in South Korean patients who underwent a platelet function test and received a double maintenance dose of clopidogrel at a secondary medical institution between January 2011 and June 2012. The primary endpoint was to assess clopidogrel response using an adenosine diphosphate test after a double maintenance dose of clopidogrel. The secondary endpoint was the presence of factors that could affect response to clopidogrel.

Results: Of 389 patients identified, 77 patients were eligible for this study. Values from the adenosine diphosphate test decreased significantly in 63 patients (82%) after a double maintenance dose of clopidogrel (p < 0.001). A total of 37 patients (48%) overcame clopidogrel resistance. Concurrent disease appeared to be a contributory factor in clopidogrel resistance.

Conclusion: A double maintenance dose of clopidogrel at 150 mg daily was associated with a reduction in adenosine diphosphate-induced platelet aggregation in South Korean patients who previously exhibited clopidogrel resistance.