|Institution:||Washington State University|
|Keywords:||Psychobiology; Public health|
|Full text PDF:||http://hdl.handle.net/2376/5206|
This study investigated the long-term analgesic efficacy of opioids and non-opioids for management of chronic low back pain. The goals were to determine if analgesic effects were maintained over time, or if analgesia was reduced as a result of tolerance and/or hyperalgesia. Another goal was to determine if analgesic efficacy significantly differed between men and women. This study was a retrospective design where data was collected from medical records of patients who have had a primary diagnosis of chronic low back pain and who have been prescribed either opioids (i.e., morphine) or non-opioids (i.e., antidepressants and anticonvulsants) for pain management. Data was collected about the amount of medication use, the pain rating, and the use of secondary medications such as NSAIDs and muscle relaxants. Data was analyzed using latent growth curve modeling, where the initial and slope values of medication use were estimated as growth trajectories, and pain ratings, secondary medication use, and patient sex were modeled as covariates. Results indicated that across time there was minimal significant change in medication use (either opioids or non-opioids) or in pain ratings. There was a significant increase in pain ratings as opioid use increased at the three and six month time points, indicating the possibility that long-term opioid use contributed to the start of hyperalgesia development. No such growth trajectory was observed with non-opioid use, indicating that opioids may uniquely contribute to hyperalgesia across time. Results also revealed that NSAID use in combination with non-opioids significantly decreased non-opioid use across time, thus NSAIDs may facilitate analgesic efficacy of non-opioids. No significant sex differences were observed in medication use or in pain levels over time, suggesting that men and women have similar patterns of medication use and pain levels. In sum, these results suggest that over time, both opioids and non-opioids do not provide a significant improvement in reducing pain levels for men and women with chronic low back pain. However, this was a clinical study with a heterogeneous sample and many external variables that could offer additional or alternative results and deserve consideration in future studies.