title: An evaluation of the completeness of drug-drug interaction-related information in package inserts.
abstract: OBJECTIVE
  The project aimed to evaluate the completeness of drug-drug interaction (DDI)-related information in package inserts (PIs) and develop a systematic approach to conduct the evaluation.
  
  
  METHODS
  DDI-related information in the branded PIs of statins, macrolides, protease inhibitors and selected drugs of narrow therapeutic index (DNTI) were evaluated against the criteria distilled from the Food and Drug Administration (FDA) labelling recommendation guidance document. Decision trees were crafted and employed in the evaluation process. Scores were computed to give each PI an overall completeness score and individual criterion completeness score. The Kruskal-Wallis test and Dunn's multiple comparison test were used to assess the differences in the completeness scores.
  
  
  RESULTS
  The mean overall completeness score of the 21 PIs was 35.7 ± 13.4 % (range 12.2-62 %). Eight out of the 11 individual evaluation criterion had a mean completeness score below 50 %. A subclass analysis conducted revealed that PIs from the different drug classes differed in the type of DDI-related information, such that they are more complete or less complete.
  
  
  CONCLUSIONS
  The completeness score of DDI-related information in the PIs varied extensively amongst and within drug classes. A consensus between the authorities and drug companies on the type and quality of DDI-related information to be included could improve their completeness in PIs and make PIs a valuable source of DDI reference. Decision trees, albeit not validated yet, lay the groundwork for a valuable tool to evaluate DDI-related or other drug information.
authors: Department of Pharmacy, National University of Singapore, 18 Science Drive 4, Singapore, 117543, Singapore.
authors: Giok Qin
authors: GQ
authors: Ng
authors: Department of Pharmacy, National University of Singapore, 18 Science Drive 4, Singapore, 117543, Singapore.
authors: Grant Edward
authors: GE
authors: Sklar
authors: Department of Pharmacy, National University of Singapore, 18 Science Drive 4, Singapore, 117543, Singapore. phacht@nus.edu.sg.
authors: Hui Ting
authors: http://orcid.org/0000-0001-8712-015X
authors: HT
authors: Chng
mesh_terms: D004347:Drug Interactions; D004348:Drug Labeling; D006801:Humans
keywords: Drug information; Drug interaction; Drug-drug interaction; Package insert