title: Impact of a health safety warning and prior authorisation on the use of piroxicam: a time-series study.
abstract: BACKGROUND
  The aim of this study was to assess the quantitative changes in systemic use of piroxicam after the issue of a health safety warning about its risks and the subsequent implementation of prior authorisation.
  
  
  METHODS
  We determined the number of monthly daily defined doses/1000 inhabitants/day (DHDs) of piroxicam in the period 2005-2008 in a health area in Spain. The data were analysed graphically, and the impact of the safety warning and introduction of prior authorisation were estimated by using segmented regression analysis.
  
  
  RESULTS
  The graph showed that the number of DHDs of piroxicam was stable both before and after the health safety warning but registered a very marked decrease after implementation of prior authorisation, after which DHDs of piroxicam remained stable at a 98% inferior level compared with previous to prior authorisation. Segmented regression analysis showed no statistically significant immediate jump in piroxicam utilisation after the safety warning nor a change in the slope afterwards, but it did show a significant immediate jump after prior authorisation.
  
  
  CONCLUSIONS
  Population exposure to systemic piroxicam remained unaffected by a previous health safety warning but declined sharply after the introduction of prior authorisation.
authors.affiliation: Santiago de Compostela Health Area, Galician Health Service, Spanish National Health System, Spain. eduardo.carracedo.martinez@sergas.es
authors.forename: Eduardo
authors.initials: E
authors.lastname: Carracedo-Martínez
authors.forename: Agustin
authors.initials: A
authors.lastname: Pia-Morandeira
authors.forename: Adolfo
authors.initials: A
authors.lastname: Figueiras
mesh_terms: D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D011307:Drug Prescriptions / Q000592:standards / Q000706:statistics & numerical data; D017723:Drug Utilization Review / Q000706:statistics & numerical data / Q000639:trends; D006801:Humans; D010894:Piroxicam / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D010818:Practice Patterns, Physicians'; D012044:Regression Analysis; D012449:Safety; D013030:Spain
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D010894:Piroxicam