title: Utilization of fentanyl buccal tablets in England: exploring off-label use reported in a cohort study.
abstract: BACKGROUND
  Fentanyl citrate buccal tablets are indicated for the treatment of breakthrough pain (BTP) in cancer, in adults who are receiving maintenance opioid therapy for chronic cancer pain.
  
  
  OBJECTIVE
  One of the objectives of this study was to describe the utilization characteristics of patients prescribed fentanyl buccal and to assess how the product is being used in relation to the terms of license of marketing approval.
  
  
  METHODS
  An observational post-marketing cohort study was conducted. For the analysis of this study, exposure data were collected from dispensed prescriptions issued by general practitioners (GPs) between March 2009 and June 2011. Outcome data (indication, event, patient demographic and selected clinical characteristics) were collected by sending questionnaires to GPs at least 6 months after the drug was first prescribed. Summary descriptive statistics were calculated.
  
  
  RESULTS
  The cohort consisted of 551 patients, of which 54.8% (n = 302 patients) were female. The median age for the cohort was 62 years (interquartile range: 50-72 years), with one patient (0.2%) aged less than 18 years. A primary indication of BTP in cancer was reported for 61.9% (n = 341) patients. Regular opioid therapy was reported upon starting the treatment for 383 patients (69.5% of cohort). In total, 69 patients (12.5%) had one or more contraindications for use. The most frequent initial titration dose was 100 μg/day (n = 247).
  
  
  CONCLUSIONS
  The final study results show that fentanyl buccal is largely being prescribed according to the terms of the license in general practice in England, but off-licence use and use in the presence of contraindications and warnings have been reported.
authors.affiliation: Drug Safety Research Unit, Southampton, UK; School of Pharmacy and Biomedical Science, University of Portsmouth, UK.
authors.forename: V
authors.initials: V
authors.lastname: Osborne
authors.forename: D
authors.initials: D
authors.lastname: Layton
authors.forename: C
authors.initials: C
authors.lastname: Fogg
authors.forename: M
authors.initials: M
authors.lastname: Al-Shukri
authors.forename: S A W
authors.initials: SA
authors.lastname: Shakir
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000701:Analgesics, Opioid / Q000627:therapeutic use*; D015331:Cohort Studies; D004739:England; D005260:Female; D005283:Fentanyl / Q000008:administration & dosage / Q000627:therapeutic use*; D006801:Humans; D008297:Male; D008875:Middle Aged; D056687:Off-Label Use; D010146:Pain / Q000188:drug therapy*; D011795:Surveys and Questionnaires; D013607:Tablets; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D000701:Analgesics, Opioid; D013607:Tablets; D005283:Fentanyl