The patient has been treated since 2009 for failed back surgery syndrome. She was diagnosed with tactile allodynia in the pelvic girdle and lower limbs. Pain intensity was rated 8/10 in the numerical rating scale (NRS). Fentanyl in transdermal system 50 μg/hr, immediate-release morphine 20 mg for breakthrough pain, amitriptyline 50 mg/day and gabapentin 900 mg/day were used. After two years of treatment symptoms of reduced pain threshold in the whole body and generalized allodynia occurred, which were recognized as hyperalgesia. Reduction of the fentanyl dose to 25 μg/hr gave no pain relief. Due to exacerbation of symptoms, opioid-rotation was carried out by replacing fentanyl with buprenorphine, initially administered sublingually, and then transdermally in the dose of 70 μg/hr.

Hyperalgesia is a complication of chronic use of opioids. Reduction of pain intensity and allodynia after the use of buprenorphine may confirm the validity of the diagnosis.