Researchers believe it may be possible to reduce the development of opioid tolerance if the compound CXCL1 is neutralized or blocked in patients taking opioids for chronic management of severe pain. Results from the study are published in the journal Anesthesiology.

CXCL1 is a protein produced by spinal cord tissue that is involved in the development of opioid tolerance. Researchers compared patients with cancer-related pain controlled by strong opioids (eg, morphine) with age-matched control subjects without cancer who were not taking opioids. What they discovered was that in both human patients and rats, those deemed opioid-tolerant and regularly given opioids had more CXCL1 vs. those not regularly given opioids.

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When rats were given more CXCL1 in the space surrounding the spinal cord, there was a greater rate of onset and severity of tolerance, proving further that the protein contributes to tolerance. During the study’s second phase, the rats were given a CXCL1 neutralizing or blocking agent that partially maintained the efficacy of the opioid.

The authors of the study acknowledge that more research will need to be done to determine whether blocking CXCL1 can safely and effectively lessen the development of opioid tolerance in patients.

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