Pharmaceutical treatment patterns for patients with a diagnosis related to chronic pain initiating a slow-release strong opioid treatment in Sweden.

Slow-release strong opioids (SRSO) are indicated in patients with severe chronic pain. Side effects, lack of efficacy and risk of dependency limit their use in clinical practice. The aim of this study was to explore prescription patterns of SRSO in Swedish real-world data on patients with a diagnosis related to chronic pain (DRCP). Patient-level data were extracted from the national prescriptions register and a regional register with diagnosis codes. The prescription sequences, switches, co-medications, and strengths over time were analyzed for cancer and noncancer patients. Of 840,000 patients with a DRCP, 16,257 initiated treatment with an SRSO in 2007 to 2008. They were 71 years old on average; 60% were female and 34% had cancer. The most common first prescription was oxycodone (54%) followed by fentanyl (19%), buprenorphine (14%), and morphine (13%). 63% refilled their prescription within 6 months, and 12% switched to another SRSO, most commonly fentanyl. After 3 years, 51% of cancer and 27% of noncancer patients still being in contact with health care remained on any SRSO. Of noncancer patients, 35% had a psychiatric co-medication (SSRI or benzodiazepine). In conclusion, fewer patients remain on SRSO in the long-term in clinical practice than reported in previous clinical trials. Oxycodone is the most common first SRSO prescription and one-third of patients get a prescription indicating psychiatric comorbidity. Our interpretation of these findings are that there is need for better treatment options for these patients, and that more effort is needed to improve treatment guidelines and to ascertain that these guidelines are followed.