Moderate
Established
Description
IV morphine delays and reduces the absorption of oral clopidogrel in acute coronary syndrome patients, potentially providing inadequate antiplatelet coverage during a critical window.
Mécanisme
Opioids slow gastric emptying via mu-receptor stimulation, delaying the transit of clopidogrel to its intestinal absorption site and reducing peak plasma concentrations and platelet inhibition.
Signification clinique
Pharmacokinetic studies in STEMI patients show that morphine reduces clopidogrel Cmax by ~34% and delays Tmax by ~1–2 hours.
Prise en charge
Consider using ticagrelor (which is less affected by morphine) instead of clopidogrel in ACS patients requiring opioid analgesia; or administer a crushed clopidogrel loading dose to partially mitigate the delay.