Prevalence and characteristics of breakthrough pain in patients receiving opioids for chronic back pain in pain specialty clinics.

Objective: We sought to assess the prevalence and characteristics of breakthrough pain (BTP) in patients with chronic back pain.

Design: Researchers utilized a telephone survey using a pain assessment algorithm. This report represents a subset of patients from a larger survey of 228 patients with chronic pain unrelated to cancer.

Participants: This study employed 117 subjects taking opioids for a primary diagnosis of back pain and receiving care at geographically dispersed pain treatment centers. Subjects had pain lasting at least six months and had "controlled" baseline pain.

Results: Eighty-seven subjects (74 percent) experienced 93 types of BTP. The median number of BTP episodes per day was two; median time to maximum intensity was 10 minutes, and median duration was 55 minutes. Onset could not be predicted for 46 percent of pains. Eighty-three percent of subjects used shorter-acting opioids for BTP. Other medications used for pain included NSAIDs, antidepressants, anticonvulsants, skeletal muscle relaxants, intrathecal local anesthetics, and transdermal local anesthetics.

Conclusions: These patients with opioid-treated chronic back pain commonly experienced BTP, which often had a rapid onset and a relatively short duration and was difficult to predict. Opioids were the mainstay of pharmacologic therapy, but nonopioid analgesics and adjuvant analgesics were commonly used.