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Diamorphine or morphine for ischaemic cardiac chest pain

Three Part Question

In [patients with a myocardial infarction] is [morphine better than diamorphine] at [alleviating chest pain]?

Clinical Scenario

A 55 year old man presents to the emergency department with chest pain. An ECG shows changes consistent with acute myocardial infarction. He is given aspirin and oxygen. His thrombolytic therapy is commenced and in the meantime you wonder whether his pain would be best alleviated by either morphine or diamorphine.

Search Strategy

Medline 1966-10/03 using the OVID ATHENS interface.
Including MEDLINE in progress and non-indexed citations.
[(exp chest pain OR exp myocardial infarction OR myocard$.mp OR infarct$.mp OR AND (exp morphine OR OR OR OR analg$.mp OR exp analgesics, opioid) AND (exp clinical trials OR exp randomized controlled trials OR randomized controlled] LIMIT to human AND English.

Search Outcome

Altogether 56 papers were identified of which only one was relevant. Details of this paper are shown in the table.

Relevant Paper(s)

Author, date and country Patient group Study type (level of evidence) Outcomes Key results Study Weaknesses
Scott ME and Orr R,
118 patients aged 30-79 yrs with moderate to severe chest painPRCTComplete pain relief at 10 min47% v 32% (p<0.05)Randomization unclear Confidence intervals not stated
Complete pain relief at 30 minNSD
Complete pain relief at 60 minNSD


This is the only paper identified that compares morphine and diamorphine in this clinical situation. The doses were fixed.

Clinical Bottom Line

There are no significant clinical differences between diamorphine and morphine in patients with chest pain.

Level of Evidence

Level 2 - Studies considered were neither 1 or 3.


  1. Scott ME, Orr R. Effects of diamorphine, methadone, morphine, and pentazocine in patients with suspected acute myocardial infarction. Lancet 1969;1;1065-7.