title: Potential drug interactions in travelers with chronic illnesses: a large retrospective cohort study.
abstract: BACKGROUND
  Data regarding the prevalence of potential interactions between travel-related medications (TRM) and chronic medications in use, or medical conditions of travelers to developing countries are limited.
  
  
  METHODS
  A retrospective cohort study of travelers to low income countries. We extracted data on demographics, travel destinations, use of chronic medications, drug allergies, and relevant medical conditions. The following TRM were evaluated: mefloquine, primaquine, doxycycline, atovaquone/proguanil, fluoroquinolone antibiotics, rifaximin, azithromycin, and acetazolamide.
  
  
  RESULTS
  A total of 16,263 travelers were included in the analysis, of whom 3299(20%) suffered from chronic illnesses and 2316(14%) reported chronic medication use. A potential drug-drug interaction with TRM was identified in 1047(45%) of travelers using chronic medication. Fluoroquinolones and azithromycin were the most commonly implicated TRMs. A potential medical condition interaction with TRM was identified in 717(22%) of travelers having chronic illnesses. acetazolamide, primaquine and mefloquine, were the most commonly TRMs implicated. Drug allergies, which can pose a relative contraindication for use of acetazolamide, were reported by 1323(8.1%) of all travelers.
  
  
  CONCLUSIONS
  Potential drug-drug and drug-disease interactions involving TRM might occur in a significant proportion of travelers with chronic medical conditions. Education of health practitioners regarding such potential drug interactions and caution when in prescribing travel-related medications is warranted.
authors.affiliation: The Center of Geographic Medicine, The Chaim Sheba Medical Center, Tel Hashomer 52621, Israel; The Departments of Internal Medicine, The Chaim Sheba Medical Center, Tel Hashomer 52621, Israel; The Sackler School of Medicine, Tel-Aviv University, Tel-Aviv 69978, Israel. Electronic address: sshmuel@netvision.net.il.
authors.forename: Shmuel
authors.initials: S
authors.lastname: Stienlauf
authors.affiliation: The Center of Geographic Medicine, The Chaim Sheba Medical Center, Tel Hashomer 52621, Israel; The Departments of Internal Medicine, The Chaim Sheba Medical Center, Tel Hashomer 52621, Israel; The Sackler School of Medicine, Tel-Aviv University, Tel-Aviv 69978, Israel. Electronic address: meltzere@zahav.net.il.
authors.forename: Eyal
authors.initials: E
authors.lastname: Meltzer
authors.affiliation: The Departments of Internal Medicine, The Chaim Sheba Medical Center, Tel Hashomer 52621, Israel; The Sackler School of Medicine, Tel-Aviv University, Tel-Aviv 69978, Israel. Electronic address: d_Kurnik@rambam.health.gov.il.
authors.forename: Daniel
authors.initials: D
authors.lastname: Kurnik
authors.affiliation: The Center of Geographic Medicine, The Chaim Sheba Medical Center, Tel Hashomer 52621, Israel; The Departments of Internal Medicine, The Chaim Sheba Medical Center, Tel Hashomer 52621, Israel; The Sackler School of Medicine, Tel-Aviv University, Tel-Aviv 69978, Israel. Electronic address: leshem@gmail.com.
authors.forename: Eyal
authors.initials: E
authors.lastname: Leshem
authors.affiliation: The Center of Geographic Medicine, The Chaim Sheba Medical Center, Tel Hashomer 52621, Israel; The Departments of Internal Medicine, The Chaim Sheba Medical Center, Tel Hashomer 52621, Israel. Electronic address: eran.kopel@mail.huji.ac.il.
authors.forename: Eran
authors.initials: E
authors.lastname: Kopel
authors.affiliation: The Sackler School of Medicine, Tel-Aviv University, Tel-Aviv 69978, Israel; The Arrow Project, The Chaim Sheba Medical Center, Tel Hashomer, 52621, Israel. Electronic address: biana.str@gmail.com.
authors.forename: Bianca
authors.initials: B
authors.lastname: Streltsin
authors.affiliation: The Center of Geographic Medicine, The Chaim Sheba Medical Center, Tel Hashomer 52621, Israel; The Departments of Internal Medicine, The Chaim Sheba Medical Center, Tel Hashomer 52621, Israel; The Sackler School of Medicine, Tel-Aviv University, Tel-Aviv 69978, Israel. Electronic address: elischwa@post.tau.ac.il.
authors.forename: Eli
authors.initials: E
authors.lastname: Schwartz
mesh_terms: D000293:Adolescent; D000328:Adult; D002908:Chronic Disease / Q000188:drug therapy* / Q000453:epidemiology*; D004347:Drug Interactions; D064420:Drug-Related Side Effects and Adverse Reactions / Q000453:epidemiology* / Q000209:etiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D014195:Travel / Q000706:statistics & numerical data*; D055815:Young Adult
keywords: Chronic disease; Chronic use of prescription drugs; Developing countries; Drug interactions; Israel; Travelers