title: Frequency of potential interactions between drugs in medical prescriptions in a city in southern Brazil.
abstract: OBJECTIVE
  Drug interactions form part of current clinical practice and they affect between 3 and 5% of polypharmacy patients. The aim of this study was to identify the frequency of potential drug-drug interactions in prescriptions for adult and elderly patients. TYPE OF STUDY AND SETTING: Cross-sectional pharmacoepidemiological survey in the Parque Verde housing project, municipality of Cascavel, Paraná, Brazil, between December 2006 and February 2007.
  
  
  METHODS
  Stratified cluster sampling, proportional to the total number of homes in the housing project, was used. The sample consisted of 95 homes and 96 male or female patients aged 19 or over, with medical prescriptions for at least two pharmaceutical drugs. Interactions were identified using DrugDigest, Medscape and Micromedex softwares.
  
  
  RESULTS
  Most of the patients were female (69.8%), married (59.4%) and in the age group of 60 years or over (56.3%), with an income less than or equal to three minimum monthly salaries (81.3%) and less than eight years of schooling (69.8%); 90.6% of the patients were living with another person. The total number of pharmaceutical drugs was 406 (average of 4.2 medications per patient). The drugs most prescribed were antihypertensives (47.5%). The frequency of drug interactions was 66.6%. Among the 154 potential drug interactions, 4.6% were classified as major, 65.6% as moderate and 20.1% as minor.
  
  
  CONCLUSIONS
  The high frequency of drug prescriptions with a potential for differentiated interactions indicates a situation that has so far been little explored, albeit a reality in household surveys.
authors.affiliation: Community Pharmacy, Cascavel, Paraná, Brazil.
authors.forename: Genici Weyh
authors.initials: GW
authors.lastname: Bleich
authors.forename: Ariana
authors.initials: A
authors.lastname: Bleich
authors.forename: Priscila
authors.initials: P
authors.lastname: Chiamulera
authors.forename: Andréia Cristina Conegero
authors.initials: AC
authors.lastname: Sanches
authors.forename: Deborah Sandra Leal Guimarães
authors.initials: DS
authors.lastname: Schneider
authors.forename: Jorge Juarez Vieira
authors.initials: JJ
authors.lastname: Teixeira
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001938:Brazil; D016000:Cluster Analysis; D003430:Cross-Sectional Studies; D004347:Drug Interactions; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019338:Polypharmacy; D055553:Prescription Drugs; D012959:Socioeconomic Factors; D055815:Young Adult
chemical_list: D055553:Prescription Drugs