Efficacy Endpoints: Pain Control
Harm Endpoints: Missed or mistaken diagnoses
Narrative: This review examined a question that has stirred controversy for decades. Based on a concern that treatment with opiates may obscure the signs and symptoms that lead to accurate diagnosis of abdominal pain, opiates were often withheld as initial treatment.
There are now 12 randomized trials of varying quality (9 adult and 3 pediatric), aggregated into one systematic review. Based on both the findings of the individual trials and also the pooled results of these trials, it is safe to say that there is no evidence of an increase in misdiagnosis or worse outcomes following the administration of opiates for pain when compared to the administration of placebo or nothing for pain.
Caveats: In the aggregated data, particularly in studies where pain was demonstrably less in the treatment group, the administration of opiates did alter physical examination findings. There were, however, no increases in patient harms, diagnostic errors, or management errors.
In the early 20th century, when diagnostic error caused by opiates was posed as a concern in a surgical textbook by Dr. Zachary Cope, morphine tartrate often came in either 30mg (1/2 grain) or 60mg (1 grain) doses. These doses may well have been adequate to obscure any diagnostic yield from abdominal examination. In the studies covered in this review the doses are smaller, typically 10mg of morphine, its equivalent, or less.
In addition, while the studies on this topic were not designed to precisely measure the degree of pain relief that the medications afforded, there was a detectable decrease in pain in the treatment arm in 8 of the 12 studies. Although we cannot list the NNT’s for this benefit (see methods for the distinction between continuous and dichotomous variables and the NNT), and the benefit depends on adequate doses it is apparent that there was a considerable benefit in pain relief for those in the opiate groups—without any increase in patient harms.
Author: David Newman, MD
Published/Updated: August 19, 2010
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