A comparison of metoprolol and morphine in the treatment of chest pain in patients with suspected acute myocardial infarction – the MEMO study

Abstract

Objectives. To compare the analgesic effect of metoprolol and morphine in patients with chest pain due to suspected or definite acute myocardial infarction after initial treatment with intravenous metoprolol.Design. All patients, regardless of age, admitted to the coronary care unit at Uddevalla Central Hospital due to suspected acute myocardial infarction were evaluated for inclusion in the MEMO study (metoprolol-morphine). The effects on chest pain and sideeffects of the two treatments were followed during 24 h. Pain was assessed by a numerical rating scale. Results.A total of 265 patients were randomized in this prospective double-blind study and 59% developed a confirmed acute myocardial infarction. In both treatment groups, there were rapid reductions of pain intensity. However, in the patient group treated with morphine, there was a more pronounced pain relief during the first 80 min after start of double-blind treatment. The side-effects were few and were those expected from each therapeutic regimen. During the first 24 h, nausea requiring anti-emetics was more common in the morphine-treated patients. Conclusion.In suspected acute myocardial infarction, if chest pain persists after intravenous betaadrenergic blockade treatment, standard doses of an opioid analgesic such as morphine will offer better pain relief than increased dosages of metoprolol.

Effect of oxygen therapy on chest pain in patients with ST elevation myocardial infarction: results from the randomized SOCCER trial

“…Many studies, e.g. [23][24][25], describe the analgesic effect of morphine in AMI patients, and we believe that the observed diminished pain was explained by the fact that the majority of our patients were given iv morphine.…”

Impact of Preadmission Morphine on Reinfarction in Patients With ST‐Elevation Myocardial Infarction Treated With Percutaneous Coronary Intervention: A Meta‐Analysis

“…Of these, two studies were excluded since only infarct size, based on cardiac magnetic resonance imaging, was reported as an outcome; a further study was excluded since it included a mixed group of patients with both STEMI and non‐ST elevation ACS where STEMI data could not be extricated; and another study was excluded as it included only patients with non‐ST elevation ACS . A further 17 studies were excluded for not reporting the clinical outcome of interest …”

Morphine in acute coronary syndrome: systematic review and meta-analysis

“…The search returned 1419 records, resulting in 1035 records after removing all duplicates. After title and abstract screening, 53 articles were assessed for full-text screening, with 17 being included for qualitative and quantitative syntheses, 5 being RCTs29–33 and 12 being observational studies 10 34–44. We did not retrieve any unpublished study (figure 1).…”