Influence of Morphine on Pharmacokinetics and Pharmacodynamics of Ticagrelor in Patients with Acute Myocardial Infarction (IMPRESSION): study protocol for a randomized controlled trial

Background: Ticagrelor is an oral platelet P2Y12 receptor antagonist which is recommended for patients suffering from myocardial infarction, both with and without persistent ST segment elevation. Morphine is the first choice drug in pain alleviation in the same clinical subset. Recently a possible negative influence of morphine on the pharmacokinetics and antiplatelet effects of P2Y12 receptor blockers has been postulated. Methods/design: The IMPRESSION study is a phase IV, single center, randomized, double-blind, placebo-controlled clinical trial that is designed to assess the influence of morphine on the pharmacokinetics and pharmacodynamics of ticagrelor in patients with myocardial infarction. The study is planned to include up to 100 patients with myocardial infarction who will be randomized into one of two arms in a 1:1 ratio. Subjects in the intervention arm prior to the loading dose of ticagrelor (180 mg) will receive morphine (5 mg) intravenously, whereas patients in the control arm will receive a placebo prior to the loading dose of ticagrelor (180 mg). The pharmacokinetics of ticagrelor and its active metabolite (AR-C124910XX) will be assessed by liquid chromatography mass spectrometry. Platelet function testing in each patient will be performed using up to four different methods (platelet vasodilator-stimulated phosphoprotein assay, multiple electrode aggregometry, VerifyNow, and light transmission aggregometry). Discussion: This study is expected to provide essential evidence-based data on the impact of morphine on the absorption of ticagrelor in patients with myocardial infarction as well as to shed some light on the suspected connection between morphine use and antiplatelet activity of ticagrelor in the same group of patients.