Summary
Increased body weight is independently associated with impaired clopidogrel pharmacodynamic
(PD) response. Prasugrel has more potent PD effects compared with clopidogrel, although
its PD effects in obese patients are unknown. The aim of this prospective, randomised,
study was to compare the PD effects of standard-dose prasugrel [60 mg loading dose
(LD)/10 mg daily maintenance dose (MD)] with highdose clopidogrel (900 mg LD/150 mg
daily MD) in non-diabetic obese [body mass index (BMI) ≥30 kg/m2] patients, with coronary artery disease (CAD) on aspirin therapy. PD assessments
(baseline, 2 hours post-LD and 6 ± 2 days after MD) were conducted using four platelet
function assays, and the platelet reactivity index (PRI) assessed by VASP was used
for sample size estimation. A total of 42 patients with a BMI of 36.42 ± 5.6 kg/m2 completed the study. There were no differences in baseline PD measures between groups.
At 2 hours post-LD, prasugrel was associated with lower PRI compared with clopidogrel
(24.3 ± 5.5 vs 58.7 ± 5.7, p≤0.001), with consistent findings for all assays. At one-week,
PRI values on prasugrel MD were lower than clopidogrel MD without reaching statistical
significance (34.7 ± 5.8 vs 42.9 ± 5.8, p=0.32), with consistent findings for all
assays. Accordingly, rates of high on-treatment platelet reactivity were markedly
reduced after prasugrel LD, but not after MD. In conclusion, in non-diabetic obese
patients with CAD, standard prasugrel dosing achieved more potent PD effects than
high-dose clopidogrel in the acute phase of treatment, but this was not sustained
during maintenance phase treatment. Whether an intensified prasugrel regimen is required
in obese patients warrants investigation.
Keywords
Platelet function - obesity - coronary artery disease - prasugrel - clopidogrel