title: A systematic review on drugs absorption modifications after eradication in Helicobacter pylori positive patients undergoing replacement therapy.
abstract: OBJECTIVE
  Helicobacter pylori (H. pylori) infection has been suggested as a cause of impaired drug absorption. This infection leads to alteration of the gastric acid secretion that may change the conformational characteristics of drugs and their intestinal absorption leading to uncertainties about the dose to administer and the therapeutic results. A systematic review was undertaken to clarify the implications of drug absorption during the administration of replacement therapies.
  
  
  METHODS
  Electronic databases such as MEDLINE/Pubmed, EMBASE and The Cochrane Library [which includes Cochrane Database of Systematic Review (CDSR), the Cochrane Central Register of Controlled Trials (CENTRAL), the Database of Abstract of Reviews of Effect (DARE)] were searched. Grey literature databases (e.g. the International clinical trials registry platform, Trials Register, Clinical Trials.gov, Controlled Trials and TrialsCentral), Theses database, Government publication and LILACS database were also searched. No language restriction was applied.
  
  
  RESULTS
  Infection and altered drug absorption were evaluated in patients under replacement therapies with iron, thyroxin and L-dopa. In all, seven studies included an improvement in drug absorption after eradication and an existing inverse correlation between the grade of gastric inflammation and indices of drug absorption were noticed.
  
  
  CONCLUSIONS
  This systematic review confirmed the presence of an interaction between infection and drug absorption of orally administered replacement therapies. Gastric acid reduction and subsequent alteration of drug composition seem to lead this mechanism. Clinicians should be aware of this possible interaction when starting a replacement therapy in patients and when evaluating poor clinical response.
authors.affiliation: Department of Medical and Surgical Sciences,University of Bologna, Bologna, Italy.
authors.forename: Giulia
authors.initials: G
authors.lastname: Fiorini
authors.affiliation: Department of Health Science, University of York, York, UK.
authors.forename: John Martin
authors.initials: JM
authors.lastname: Bland
authors.affiliation: Department of Health Science, University of York, York, UK.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Hughes
authors.affiliation: Department of Medical and Surgical Sciences,University of Bologna, Bologna, Italy.
authors.forename: Valentina
authors.initials: V
authors.lastname: Castelli
authors.affiliation: Department of Medical and Surgical Sciences,University of Bologna, Bologna, Italy. berardino.vaira@unibo.it.
authors.forename: Dino
authors.initials: D
authors.lastname: Vaira
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D005744:Gastric Acid / Q000378:metabolism; D005753:Gastric Mucosa / Q000187:drug effects* / Q000378:metabolism / Q000382:microbiology; D016481:Helicobacter Infections / Q000175:diagnosis / Q000188:drug therapy* / Q000382:microbiology / Q000503:physiopathology; D016480:Helicobacter pylori / Q000187:drug effects* / Q000254:growth & development; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007408:Intestinal Absorption; D058085:Iron Compounds / Q000008:administration & dosage / Q000378:metabolism*; D007980:Levodopa / Q000008:administration & dosage / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D012074:Remission Induction; D013974:Thyroxine / Q000008:administration & dosage / Q000378:metabolism*; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D058085:Iron Compounds; D007980:Levodopa; D013974:Thyroxine