An analysis by researchers from the Duke Clinical Research Institute has shown that patients hospitalized for non–ST-segment elevation acute coronary syndromes ( NSTE ACS ) and treated with Morphine to relieve chest pain, have almost a 50 percent higher risk of dying.

In the analysis of the clinical data and outcomes of more than 57,000 patients, the researchers found that those who received Morphine had a 6.8 percent death rate, compared to 3.8 percent for those receiving Nitroglycerin.

" The results of this analysis raise serious concerns about the safety of the routine use of Morphine in this group of heart patients, " said Duke cardiologist Trip Meine, the study's lead author. " Since randomized clinical trials evaluating the safety or effectiveness of Morphine for these patients have not been conducted, official guidelines for its use are based solely on expert conjecture. Given the adverse outcomes associated with Morphine use found in our analysis, a randomized clinical trial is in order. "

Morphine was first used to relieve the chest pain associated with heart attacks in 1912 and has been used regularly ever since.
Nitroglycerin has been used for more than 130 years for the relief of chest pain, also known as unstable angina. It works by relaxing blood vessels and allowing blood flow to increase.

" Nitroglycerin has a physiological effect that may, at least temporarily, influence the underlying ischemia, " Meine said. " Morphine, on the other hand, doesn't do anything about what is actually causing the pain. It just masks it, and may, in fact, make the underlying disease worse.
Morphine has the well-known and potentially harmful side effects of depressing respiration, reducing blood pressure and slowing heart rate, " he continued. " These side effects could explain the worse outcomes in patients whose heart function has already been compromised by disease. "

For their analysis, the researchers consulted the Nationwide Quality Improvement Initiative named CRUSADE ( Can Rapid Risk Stratification of Unstable Angina Patients Suppress Adverse Outcomes with Early Implementation of the American College of Cardiology and AHA Guidelines ). The registry continually collects data from more than 400 hospitals on outcomes and on the use of proven drugs and procedures used to restore blood flow to the heart.

A total of 17,003 patients ( 29.8% ) received Morphine within 24 hours of presentation. Patients treated with Morphine had a higher risk of death ( odds ratio [OR] 1.48 ) than patients not treated with the drug.

Relative to those receiving Nitroglycerin, patients treated with Morphine also had a higher likelihood of death ( OR 1.50 ).

The use of Morphine was associated with increased inhospital mortality ( OR 1.41 ). The increased risk of death in patients receiving Morphine persisted across all measured subgroups.

" Our recommendation is that patients should begin with full dose of Nitroglycerin to control pain," Meine said. " Based on our analysis, Morphine should be the last resort after else has been tried. "

Source: American Heart Journal, 2005


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