A 68 year old female patient, who came to the pain clinic referred by her GP, diagnosed with severe spondyloarthrosis, mainly at the expense of the lumbar spine. She had been prescribed generic transdermal fentanyl 25 μg/h for 2 weeks, with regular pain control (VAS, 7-8). After examination of the patient, the exchange of generic fentanyl for Durogesic® Matrix 25 μg/h was considered. After 2 weeks, the patient presented better pain control (VAS, 3-4), requiring 1 g paracetamol on its own as a rescue treatment. At 3 months she continues with Durogesic® Matrix 25 μg/h, with acceptable pain control (VAS, 3), and sporadically, as a rescue, paracetamol 1 g.