[Altered pain thresholds during and after opioid withdrawal in patients with chronic low back pain]

Opioids as the strongest pain drugs are often used for chronic pain although their long-term efficacy has not yet been clarified. In this longitudinal study, we compared the pain sensitivity of patients with chronic low back pain (cLBP) under long-term opioid use and treated with multidisciplinary pain therapy.

The pain sensitivity was measured by the quantitative sensory testing (QST) technique at admission, discharge and 6 months after the beginning of the study in 34 patients with both cLBP and opioid medication, 33 opioid-naive cLBP patients and those neither with pain nor opioid use (HC). Both patient groups underwent a 3-week multidisciplinary pain therapy (MDPT).

Under opioid use, the patients showed significantly lower cold and heat pain thresholds compared to HC and delayed reaction to warm stimuli. After 3 weeks of MDPT, opioid-positive patients still had a lower pain threshold to cold and heat stimuli, while opioid-naive patients normalised their pain perception.

Our findings suggest that long-term use of opioids intensifies the peripheral sensitisation of cLBP. The MDPT can counteract this process.