Abstract 11449: Morphine Delays the Onset of Action of Prasugrel in Patients With Prior History of St Elevation Myocardial Infarction
Background: Patients undergoing primary percutaneous coronary intervention (PPCI) for ST-elevation myocardial infarction (STEMI) receive loading doses of aspirin and a P2Y12 inhibitor. Delays in onset of action of all P2Y12 inhibitors are reported in PPCI patients and this may increase the risk of acute stent thrombosis. Morphine is known to delay the absorption of orally administered drugs.
Aim: To determine whether morphine delays the onset of action of prasugrel in patients with previous PPCI for STEMI.
Methods: This was an open-label, crossover study 12 aspirin-treated patients with a history of STEMI treated with PPCI for which prasugrel and morphine had been administered. Patients were randomly assigned to receive either morphine 5mg or saline intravenously followed by 60mg prasugrel. Blood samples were collected before and over 24 hours after drug administration and platelet function testing using VerifyNow P2Y12 assay and light transmittance aggregometry (LTA) was performed. After a washout period of 3 weeks, patients then crossed over. The primary endpoint of the study was platelet reaction units (PRU) assessed by VerifyNow P2Y12 assay at 2 hours post prasugrel.
Results: 11 patients completed the study. Mean PRU at 2h post prasugrel was 26 ± 36 PRU with saline and 104 ± 110 PRU with morphine (P = 0.027). Final LTA response to ADP 20 uM at 2h post prasugrel was 5 ± 12% with saline and 23 ± 28% with morphine (P = 0.033). The mean estimated time taken to achieve a PRU of 150 was 50 ± 34 mins with saline and 151 ± 181 mins with morphine. There was no difference in platelet reactivity at 24h post prasugrel with saline compared to morphine (20 ± 27 PRU saline vs 19 ± 29 PRU morphine).
Conclusions: Morphine delays the onset of action of prasugrel in patients with a prior history of PPCI for STEMI. Intravenous drugs may be necessary to reduce the risk of acute stent thrombosis in morphine-treated STEMI patients undergoing PPCI.
- © 2013 by American Heart Association, Inc.