Swapping out intravenous fentanyl in favor of IV acetaminophen in patients with ST-elevation MI (STEMI) provides comparable pain relief but with desirably higher blood levels of ticagrelor both immediately after primary percutaneous intervention and 1 hour post procedure.
That’s according to results of the Dutch ON-TIME 3 trial, presented by Anne H. Tavenier, MD, at the virtual annual meeting of the European Association of Percutaneous Cardiovascular Interventions.
“Our trial results have implications for the prehospital treatment of STEMI patients,” said Dr. Tavenier, a cardiologist at the Isala Clinic in Zwolle, the Netherlands.
The explanation for the success of this novel STEMI pain management strategy? The synthetic opioid fentanyl impairs gastrointestinal absorption of oral P2Y12 receptor antagonists such as ticagrelor. Opiates do so as well, whereas acetaminophen does not, she explained.
The potent platelet inhibition provided by oral P2Y12 inhibitors is crucial to successful primary PCI for STEMI. But these platelet inhibitory effects are inherently slowed in STEMI patients owing to hemodynamic changes and delayed GI absorption. And even though both American College of Cardiology/American Heart Association and European Society of Cardiology guidelines recommend the use of opioids for pain control in STEMI patients, the fact is that these medications further delay the absorption of oral P2Y12 inhibitors. And this delay is further exacerbated by the nausea and vomiting which are common side effects of IV fentanyl, she continued.
The impetus for the ON-TIME 3 trial was straightforward, the cardiologist said: “For years, STEMI patients have been treated with morphine or morphinelike drugs like fentanyl because of pain or sympathetic stress. To date, trials investigating alternative analgesics to opioids have been scarce.”
ON-TIME 3 was a multicenter, open-label, phase 4 clinical trial in which 195 STEMI patients with a self-reported pain score of at least 4 on a 0-10 scale received crushed ticagrelor in the ambulance along with either 1,000 mg of IV acetaminophen or fentanyl at 1-2 mcg/kg.
Ticagrelor blood levels were significantly higher in the IV acetaminophen group when measured just prior to primary PCI (151 ng/mL versus 60 ng/mL in the IV fentanyl group; immediately after PCI (326 versus 115 ng/mL), and 1 hour post PCI (488 versus 372 ng/mL).
However, there was no significant between-group difference in levels of platelet reactivity units measured immediately after primary PCI, Dr. Tavenier added.
Discussant Christoph K. Naber, MD, PhD, confessed that prior to ON-TIME 3 he was unaware that administering opioids to STEMI patients results in delayed absorption of oral P2Y12 inhibitors. Upon delving into the literature, however, he found that this is indeed a well-documented problem.
“The open question I have about this very elegant trial is whether the increased P2Y12 levels will translate into a measurable difference in clinical outcomes,” said Dr. Naber, an interventional cardiologist at the Wilhemshaven (Germany) Clinic.
The answer to that question would require a larger, longer-term trial. And he’s disinclined to wait around for that to happen.
“I think when we look at the risk balance, the risk of switching from an opioid to acetaminophen, if it works for the patient, is rather low. So this might be something to introduce in my practice,” the cardiologist said.
Dr. Tavenier and Dr. Naber reported having no financial conflicts of interest.
SOURCE: Tavenier AH. EuroPCR 2020.