title: Drug interactions in oncology: how common are they?
abstract: BACKGROUND
  Drug-drug interactions (DDIs) comprise an important problem in medical oncology practice. We systematically reviewed the frequency of DDIs in oncology.
  
  
  METHODS
  We searched PubMed for eligible articles and on-line databases for abstracts of major oncology meetings.
  
  
  RESULTS
  Eight studies reported on the frequency of DDIs: six evaluated the frequency of potential DDIs, while two studies reported on real DDIs, i.e. interactions that had clinical consequences. Studies of potential DDIs found that approximately one-third of patients are exposed to dangerous drug doublets, with the most common ones involving warfarin and anticonvulsants. One study of real DDIs found that 2% of hospitalized cancer patients had a DDI as the cause of admission.
  
  
  CONCLUSIONS
  Drug interactions comprise an important issue in oncology, with approximately one-third of ambulatory cancer patients being at risk of DDIs. Data are limited on the clinical consequences of drug interactions among cancer patients.
authors.affiliation: Internal Medicine, Federal University of Sao Paulo, Sao Paulo, Brazil. rachelri@terra.com.br
authors.forename: R P
authors.initials: RP
authors.lastname: Riechelmann
authors.forename: A
authors.initials: A
authors.lastname: Del Giglio
mesh_terms: D000970:Antineoplastic Agents / Q000009:adverse effects / Q000627:therapeutic use*; D004347:Drug Interactions; D006801:Humans; D008495:Medical Oncology
chemical_list: D000970:Antineoplastic Agents