Impact of morphine on antiplatelet effects of oral P2Y12 receptor inhibitors

Morphine and P2Y12 receptor inhibitors are both recommended in patients with acute myocardial infarction. Morphine may impede gastrointestinal absorption of several oral drugs including P2Y12 platelet receptor inhibitors. The aim of this review was to critically discuss drug–drug interactions between oral P2Y12 receptor inhibitors and morphine according to currently available knowledge based on the findings of experimental, observational and randomized clinical studies. The morphine–clopidogrel pharmacodynamic interaction has been observed in numerous trials and it has been proposed as an explanation for the negative impact of morphine on the clinical outcomes in patients with acute coronary syndromes. An analogous morphine interaction with ticagrelor and prasugrel was found in several observational studies and finally proven in randomized trials in healthy volunteers and acute myocardial infarction patients. Morphine delays and attenuates exposure and antiplatelet action of oral P2Y12 receptor inhibitors in patients with myocardial infarction. Although this interaction may have potentially harmful consequences, routine avoidance of morphine cannot be recommended until clinically powered trials are completed.