Identifying best candidates for opioid pain management among low back pain patients
Endogenous opioid function and anger expressiveness appear to be useful in identifying chronic low back pain patients who are optimal candidates for opioid pain management, according to a study.
With the aim of addressing the lack of a sound method of identifying optimal opioid candidates, researchers examined 89 patients with chronic low back pain and 102 healthy controls. All participants underwent ischaemic pain induction under placebo, opioid blockade (naloxone) and morphine in counterbalanced order.
Anger expressiveness was evaluated using the Spielberger Anger-out subscale. Interactions among endogenous opioid function, anger-out scores and pain status in both patients and controls were evaluated with regard to morphine responses to ischaemic threshold, tolerance and pain intensity (McGill Sensory and Affective subscales), and side effects.
Results indicated that interactions between endogenous opioid function and anger-out scores identified subgroups with different patterns of morphine analgesia and side effects.
Among chronic pain patients and healthy controls, individuals with low endogenous opioid function and low anger-out scores showed the greatest morphine analgesic responses. On the other hand, the responses were relatively weaker for those with low endogenous opioid function and high anger-out scores.
Furthermore, the reported adverse effects with morphine were few among chronic pain patients with low endogenous opioid function and low anger-out scores, and many among those with low endogenous opioid function and high anger-out scores.
The current data shed light on which chronic pain patients may strike a favourable balance of good analgesia with few side effects vs those who may have an unfavourable balance of poor analgesia and many side effects.
While opioid prescriptions for chronic low back pain have increased in recent years, some patients do not achieve a satisfactory response to treatment. It is thus important to identify which patients are most likely to have a good, long-term response to opioid therapy in order to prevent unnecessary exposure to ineffective treatments or side effects. [Pain 2013;154:1038–1044; BMC Medicine 2007;5:39]