Prasugrel more effective than double-dose clopidogrel at reducing platelet reactivity
MedWire News: Platelet reactivity (PR) in patients with high on-treatment platelet reactivity (HTPR) following chronic clopidogrel therapy is more effectively inhibited by prasugrel than double clopidogrel dosing, the results of a Greek study indicate.
HTPR in patients receiving dual antiplatelet therapy with aspirin and clopidogrel for acute coronary syndrome or when undergoing percutaneous coronary intervention has been linked to an increased risk for adverse events, explain Dimitrios Alexopoulos from Patras University Hospital Rio, and colleagues.
They conducted a prospective, single-center, single-blinded, investigator-initiated randomized, crossover study in which 31 patients with HTPR receiving clopidogrel for ≥12 months were assigned to receive prasugrel 10 mg/day or high-dose clopidogrel 150 mg/day for 14 days, before crossing over to the alternative treatment.
All patients had stable coronary artery disease, and 87.1% had undergone a previous percutaneous coronary intervention. The VerifyNow assay was used to measure PR in platelet reactivity units (PRU).
The results showed that PR was significantly lower with prasugrel than with high-dose clopidogrel, at 148.1 versus 219.8 PRU, respectively. There was also a significant period effect of prasugrel, with PR lower post-crossover than pre-crossover, at a mean difference of 33.9 PRU.
For the secondary endpoint of HTPR, the rate was again significantly lower for prasugrel than clopidogrel, at 11.5% versus 46.3%, respectively, the team reports in the American Heart Journal. Two patients, one for each drug, discontinued treatment due to adverse effects.
The team writes: "Although our study was purely pharmacodynamic and it can be considered as only hypothesis generating, it is tempting to suggest a tailored antiplatelet treatment as a possible way to improve platelet inhibition in chronic coronary artery disease patients receiving clopidogrel, at least in those with high atherothrombotic risk."
By Liam Davenport