Administration of a loading dose has no additive effect on platelet aggregation during the switch from ongoing clopidogrel treatment to ticagrelor in patients with acute coronary syndrome.
BACKGROUND
Ticagrelor outperforms clopidogrel in preventing cardiovascular events in acute coronary syndrome. Despite the inclusion of a loading dose in the Platelet Inhibition and Patient Outcomes (PLATO) trial for all patients randomized to ticagrelor, it may not be necessary in patients receiving ongoing clopidogrel therapy. The aim of the present study was to assess whether a ticagrelor loading dose is associated with a further platelet inhibition during the switch from clopidogrel to ticagrelor in patients with acute coronary syndrome receiving ongoing antiplatelet treatment.


RESULTS
Fifty patients with acute coronary syndrome receiving aspirin and clopidogrel treatment were randomly assigned to a starting dose of ticagrelor (group 1, 90 mg; group 2, 180 mg). Platelet aggregation was measured using multiple electrode aggregometry and standard light transmission aggregometry just before the switch and at 2, 6, 24, and 72 hours. No relevant difference in platelet aggregation was observed between the 2 study arms at baseline (P=0.256). Residual platelet aggregation was significantly reduced in both arms 2 hours after the first administration of ticagrelor (P<0.001 for both), with no difference in aggregation between groups (multiple electrode aggregometry, 17.6±7.2 versus 18.1±6 U; P=0.281). Similar results were observed with LTA.


CONCLUSIONS
Switching from clopidogrel to ticagrelor without a reloading dose is feasible, and it does not hinder platelet aggregation inhibition in patients with acute coronary syndrome. Further prospective studies are needed to assess the clinical relevance of our findings.


BACKGROUND
http://www.clinicaltrials.gov. Unique identifier: NCT01795820.
From the Division of Cardiology, Department of Medical and Surgical Sciences (G.C., S.D.R., D.T., C.S., A.M., S.G., M.M., C.I.) and Clinical Pathology Unit, Department of Health Sciences (E.P., E.G.), Magna Graecia University of Catanzaro, Catanzaro, Italy; and URT-CNR, Department of Medicine, Consiglio Nazionale delle Ricerche, Catanzaro, Italy (C.I.).
Gianluca
G
Caiazzo
Salvatore
S
De Rosa
Daniele
D
Torella
Carmen
C
Spaccarotella
Annalisa
A
Mongiardo
Salvatore
S
Giampà
Mariella
M
Micieli
Eleonora
E
Palella
Elio
E
Gulletta
Ciro
C
Indolfi
D054058:Acute Coronary Syndrome / Q000188:drug therapy*; D000241:Adenosine / Q000008:administration & dosage / Q000009:adverse effects / Q000031:analogs & derivatives*; D000368:Aged; D000077144:Clopidogrel; D054796:Drug Dosage Calculations; D057915:Drug Substitution; D004357:Drug Synergism; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010974:Platelet Aggregation / Q000187:drug effects; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage* / Q000009:adverse effects; D010979:Platelet Function Tests; D000077486:Ticagrelor; D013988:Ticlopidine / Q000008:administration & dosage / Q000009:adverse effects / Q000031:analogs & derivatives*; D016896:Treatment Outcome
D010975:Platelet Aggregation Inhibitors; D000077144:Clopidogrel; D000077486:Ticagrelor; D000241:Adenosine; D013988:Ticlopidine
acute coronary syndrome; platelet aggregation; ticagrelor