title: Understanding flucloxacillin prescribing trends and treatment non-response in UK primary care: a Clinical Practice Research Datalink (CPRD) study.
abstract: The volume of prescribed antibiotics is associated with antimicrobial resistance and, unlike most other antibiotic classes, flucloxacillin prescribing has increased. We aimed to describe UK primary care flucloxacillin prescribing and factors associated with subsequent antibiotic prescribing as a proxy for non-response.
  
  
  
  Clinical Practice Research Datalink patients with acute prescriptions for oral flucloxacillin between January 2004 and December 2013, prescription details, associated Read codes and patient demographics were identified. Monthly prescribing rates were plotted and logistic regression identified factors associated with having a subsequent antibiotic prescription within 28 days.
  
  
  
  3 031 179 acute prescriptions for 1 667 431 patients were included. Average monthly prescription rates increased from 4.74 prescriptions per 1000 patient-months in 2004 to 5.74 (increase of 21.1%) in 2013. The highest prescribing rates and the largest increases in rates were seen in older adults (70+ years), but the overall increase in prescribing was not accounted for by an ageing population. Prescribing 500 mg tablets/capsules rather than 250 mg became more common. Children were frequently prescribed low doses and small volumes (5 day course) and prescribing declined for children, including for impetigo. Only 4.2% of new prescriptions involved co-prescription of another antibiotic. Age (<5 and ≥60 years), diagnosis of 'cellulitis or abscess' or no associated code, and 500 mg dose were associated with a subsequent antibiotic prescription, which occurred after 17.6% of first prescriptions.
  
  
  
  There is a need to understand better the reasons for increased prescribing of flucloxacillin in primary care, optimal dosing (and the need to co-prescribe other antibiotics) and the reasons why one in five patients are prescribed a further antibiotic within 4 weeks.
authors.affiliation: Division of Population Medicine, School of Medicine, Cardiff University, 3rd Floor, Neuadd Meirionnydd, Heath Park, Cardiff CF14 4YS, UK francisna@cf.ac.uk.
authors.forename: Nick A
authors.initials: NA
authors.lastname: Francis
authors.affiliation: Centre for Trials Research, College of Biomedical & Life Sciences, Cardiff University, 7th Floor, Neuadd Meirionnydd, Heath Park, Cardiff CF14 4YS, UK.
authors.forename: Kerenza
authors.initials: K
authors.lastname: Hood
authors.affiliation: Farr Institute, Swansea University Medical School, Singleton Park SA2 8PP, UK.
authors.forename: Ronan
authors.initials: R
authors.lastname: Lyons
authors.affiliation: Nuffield Department of Primary Care Health Sciences, University of Oxford, New Radcliffe House, Radcliffe Observatory Quarter, Woodstock Road, Oxford OX2 6NW, UK.
authors.forename: Christopher C
authors.initials: CC
authors.lastname: Butler
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D002648:Child; D002675:Child, Preschool; D004363:Drug Utilization / Q000639:trends*; D005260:Female; D005436:Floxacillin / Q000627:therapeutic use*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D010818:Practice Patterns, Physicians' / Q000639:trends*; D055656:Prescriptions; D011320:Primary Health Care / Q000379:methods*; D006113:United Kingdom; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents; D005436:Floxacillin