title: Quality of drug label information on QT interval prolongation.
abstract: BACKGROUND
  Information regarding QT-prolongation in the drug label may vary between products. This could lead to suboptimal risk minimization strategies.
  
  
  OBJECTIVE
  To systematically assess the variation in the extent and content of information on QT prolongation in the summary of product characteristics (SPC) of recently approved medicinal products.
  
  
  METHODS
  Drug labels of products centrally approved in Europe between 2006 and 2012 were screened. Of drugs including the term 'QT' in the SPC, the message on QT-prolongation ('no prolongation'/'unclear drug-QT association'/'possibly QT-prolongation'/'QT-prolongation') and the advice on cautionary measures pertaining to QT-prolongation in the label were examined, as well as their association.
  
  
  RESULTS
  Of the 175 screened products, 44 contained information on QT in the SPC ('no QT-prolongation': 23%, 'unclear drug-QT association': 43%, 'possibly QT-prolongation': 16%, 'QT-prolongation': 18%). 62% contained advices to act with caution in patients with additional risk factors for QT-prolongation. Products that more likely to have QT-prolonging properties according to the SPC provided more information on QT-prolongation in the SPC ('no prolongation': 10% and for the category 'QT-prolongation': 100%).
  
  
  CONCLUSIONS
  The extent and content of information on QT-prolongation varies considerably between SPCs, and in almost half of the drugs a clear message on QT-prolongation was lacking in the SPC.
authors.affiliation: Division of Pharmacoepidemiology and Clinical Pharmacology, Utrecht University, Utrecht, The Netherlands Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Miriam J
authors.initials: MJ
authors.lastname: Warnier
authors.affiliation: Medicines Evaluation Board (CBG-MEB), Utrecht, The Netherlands Department of Clinical Pharmacology, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: Frank A
authors.initials: FA
authors.lastname: Holtkamp
authors.affiliation: Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Frans H
authors.initials: FH
authors.lastname: Rutten
authors.affiliation: Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Arno W
authors.initials: AW
authors.lastname: Hoes
authors.affiliation: Division of Pharmacoepidemiology and Clinical Pharmacology, Utrecht University, Utrecht, The Netherlands.
authors.forename: Anthonius
authors.initials: A
authors.lastname: de Boer
authors.affiliation: Medicines Evaluation Board (CBG-MEB), Utrecht, The Netherlands Department of Clinical Pharmacology, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: Peter G M
authors.initials: PG
authors.lastname: Mol
authors.affiliation: Division of Pharmacoepidemiology and Clinical Pharmacology, Utrecht University, Utrecht, The Netherlands Medicines Evaluation Board (CBG-MEB), Utrecht, The Netherlands.
authors.forename: Marie L
authors.initials: ML
authors.lastname: De Bruin
mesh_terms: D001145:Arrhythmias, Cardiac / Q000139:chemically induced*; D053840:Brugada Syndrome; D000075224:Cardiac Conduction System Disease; D004348:Drug Labeling / Q000592:standards*; D064420:Drug-Related Side Effects and Adverse Reactions; D004562:Electrocardiography; D005060:Europe; D007722:Health Knowledge, Attitudes, Practice; D006329:Heart Conduction System / Q000002:abnormalities*; D006801:Humans; D010353:Patient Education as Topic; D018570:Risk Assessment; D012307:Risk Factors
keywords: Cardiovascular agents/adverse effects; communication; drug approval; drug labeling/legislation & jurisprudence; torsades de pointes/chemically induced