Researchers from the National Taiwan University College of Medicine report the identification of a compound that appears to contribute to the development of opioid tolerance. For patients on long-term opioid therapy for chronic pain, it may therefore be possible to forestall the onset of opioid tolerance by neutralizing or otherwise blocking the compound. By suppressing tolerance, patients may be provided better pain relief without the side effects of increased opioid dosage. The study appears in the March 2015 issue of Anesthesiology.
The compound, CXCL1, is a protein produced by spinal cord tissue. In the study, the first to examine both human patients and rats, the authors report that subjects, both human cancer patients and rats, who were regularly given opioids and deemed opioid tolerant had an increased concentration of CXCL1 compared to those not regularly administered opioids. The rats were given additional CXCL1 in the space surrounding the spinal cord, which increased the rate of onset and severity of tolerance. In a second phase of the study, the rats were administered a CXCL1 neutralizing or blocking agent that at least partially maintained the effectiveness of the opioid.
Read a news story about the discovery here.