By Ed Susman, Contributing Writer, MedPage Today
NEW ORLEANS -- Even after long-term treatment with opioids, inflammation persists in many chronic pain patients as evidenced by C-reactive protein levels and erythrocyte sedimentation rate, a California researcher reported here.
Of the 40 patients taking high dose opioids, over 100 mg equivalents of morphine a day, 8 individuals (20%) were found to have high levels of the inflammatory markers, said Forest Tennant, MD, director of the Veract Intractable Pain Clinic in West Covina.
"The elevated inflammatory markers suggest that the underlying cause of pain is still active or there may be on-going neuroinflammation related to centralized pain," Tennant stated in his poster presentation at the annual meeting of the American Pain Society.
He also reported that 12 patients had abnormal hormone levels, the most common of which was low serum pregnenolone, found in 4 (10%) of the patients.
"All 40 patients reported sustained pain control on a stable opioid dosage and improvements in one or more physiological functions," Tennant reported. The only category in which patients failed to consistently report better results was for vision, for which 5% of patients said their vision was better and 5% said it got worse. The rest of the patients responding to the questionnaire reported no change in vision.
He evaluated outcomes among 40 patients treated at his clinic between July and October 2012, all of who received high dose opioid therapy for the past 10 or more years. Prior to opioid therapy, all of these patients received multiple non-opioid treatments. Patients claimed constant, debilitating pain with severe insomnia.
The evaluation included two questionnaires; one asked about depression, hopelessness, and quality of life before and during opioid treatment and the other about improvement in 17 physiologic functions.
"Every patient reported improvement in depression, hopelessness, and quality of life," said Tennant.
Patients experienced great improvement in several functions such as: movement, 77.5%; concentration, 67.5%; walking, 62.5%; sleeping, 62.5%; appetite, 50%; memory, 42.5%; reading, 42.5%; and libido, 40%.
Hormonal suppression was a complication in 8 patients: corticotropin (2; 5.0%), cortisol (3; 7.5%), testosterone (2; 5.0%), and pregnenolone (4; 10.0%).
"The high dose opioid patients studied here greatly improved many physiologic functions and mental outlook," he reported.
David Craig, PharmD, clinical pharmacist specialist at Moffitt Cancer Center at the University of South Florida, Tampa, told MedPage Today:
"One of the questions I would have about this study is whether the patients with ongoing inflammation have some underlying condition that is causing the inflammation. If these patients have non-cancer low back pain, for example, then the inflammation finding would be more interesting than if these patients had another condition such as rheumatoid arthritis or lupus."
Craig, a former member of the APS board of directors, also said, "There have been animal studies that suggest that opioids depress immunity, and that may be what this study is getting at, that maybe there is some interplay between the presence of opioids and the depression of the immune system."
