Effect of Chewing vs Swallowing Ticagrelor on Platelet Inhibition in Patients With ST-Segment Elevation Myocardial Infarction

Abstract

Dual anti-platelet therapy represents standard care for treating patients with ST-segment elevation myocardial infarction (STEMI). Ticagrelor is a direct-acting P2Y12 inhibitor and, unlike clopidogrel and prasugrel, does not require metabolic activation. To evaluate whether chewing a loading dose (LD) of ticagrelor, 180 mg, vs traditional oral administration of an equal dose enhances platelet inhibition at 30 minutes and 1 hour after LD administration in patients with STEMI. A randomized clinical trial was conducted in adults aged 30 to 87 years from May to October 2016 in a large tertiary care center. Analyses were intention-to-treat. Fifty patients with STEMI were randomized to either chewing an LD of ticagrelor, 180 mg, or standard oral administration of an equal dose. P2Y12 reaction units were evaluated using VerifyNow (Accumentrics) at baseline, 30 minutes, 1 hour, and 4 hours after LD. Baseline characteristics were similar in both groups. The mean (SD) of P2Y12 reaction units in the chewing group compared with the standard group at baseline, 30 minutes, 1 hour, and 4 hours after ticagrelor LD were 224 (33) vs 219 (44) (95% CI, -16.77 to 27.73; P = .26), 168 (78) vs 230 (69) (95% CI, -103.77 to -19.75; P = .003), 106 (90) vs 181 (89) (95% CI, -125.15 to -26.29; P = .005), and 43 (41) vs 51 (61) (95% CI, -36.34 to 21.14; P = .30), respectively. Platelet reactivity in the chewing group was significantly reduced by 24% at 30 minutes after LD (95% CI, 19.75 to 103.77; P = .001). The relative inhibition of platelet aggregation in the chewing vs the standard group were 51% vs 10% (95% CI, 13.69 to 67.67; P = .005) at 1 hour and 81% vs 76% (95% CI, -12.32 to 16.79; P = .24) at 4 hours, respectively. Major adverse cardiac and cardiovascular event rate at 30 days was low (4%) and occurred in 1 patient in each group (95% CI, 0.06 to 16.93; P > .99). Chewing an LD of ticagrelor, 180 mg, in patients with STEMI is feasible and facilitates better early platelet inhibition compared with a standard oral LD. Larger studies are warranted to see if our preliminary findings translate into clinical outcomes. clinicaltrials.gov Identifier: NCT02725099.