Drug utilization study on immediate release Fentanyl in Spain. Prevalence, incidence, and indication.

Purpose: We aimed to characterize the trends of immediate release fentanyl (IRF) use in Spain between 2012 and 2017 and indication for its use. IRF drugs are rapid-acting opioids approved to treat breakthrough cancer pain (BTCP) in patients already receiving maintenance opioid therapy for chronic cancer pain. A substantial increase in consumption of IRF has been observed with emerging cases of abuse and dependence, most of them in noncancer patients.

Methods: An ecological descriptive consumption study with aggregated data from drug dispensed by community pharmacies and reimbursed by the National Health System in which Defined Daily Doses per 10 000 inhabitants (DID) were calculated and a retrospective cohort study using data from the Spanish Database for Pharmacoepidemiological Research in Primary Care in which participants entered the cohort study after 1 year with the Primary Care Practitioners were performed. Annual prevalence and incidence rate of IRF use were estimated by sex and calendar year. Potential indication was also assessed.

Results: IRF use in Spain increased from 2.1 DID in 2012 to 3.8 DID in 2017. The incidence rate and prevalence increased in 53% and 74%, respectively. Patients without previous cancer or BCTP diagnosis represented 27% of incident users, predominantly women. Half of patients with noncancer-related diagnosis had a musculoskeletal disorder linked to the first IRF prescription.

Conclusions: National consumption and new IRF users in Spain increased over the study period and one quarter of patients did not have a BTCP or cancer diagnosis registered in their clinical record.