title: Systematic review: impaired drug absorption related to the co-administration of antisecretory therapy.
abstract: BACKGROUND
  Due to suppression of gastric acidity during antisecretory therapy, an impaired absorption of co-administered drugs may occur.
  
  
  OBJECTIVE
  To review evidence of impaired drug absorption related to the use of co-administered PPIs or H2RAs.
  
  
  METHODS
  Systematic search of MEDLINE/EMBASE/SCOPUS databases (1980-September 2008) for English articles with keywords: drug malabsorption and absorption, stomach, anti-secretory/acid inhibitory drugs, histamine H2 antagonists, PPIs, gastric acid, pH, hypochlorhydria, gastric hypoacidity. From 2126 retrieved articles, 16 randomized crossover studies were identified investigating impaired absorption of nine different drugs in association with co-administration of PPIs or H2RAs. Information on investigated drug, study type, features of investigated subjects, study design, type of intervention, and study results were extracted.
  
  
  RESULTS
  The identified studies investigated the absorption kinetics of nine drugs. Acid suppression reduced absorption of ketoconazole, itraconazole, atazanavir, cefpodoxime, enoxacin and dipyridamole (median C(max) reduction by 66.5%). An increased absorption of nifedipine and digoxin (median AUC increase by 10%) and a 2-fold-increase in alendronate bioavailability were observed.
  
  
  CONCLUSIONS
  Gastric pH appears relevant for absorption of some cardiovascular or infectious disease agents. Antisecretory treatment may significantly modify the absorption of co-administered drugs.
authors.affiliation: Digestive and Liver Disease Unit, 2nd School of Medicine, University La Sapienza, Rome, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Lahner
authors.forename: B
authors.initials: B
authors.lastname: Annibale
authors.forename: G
authors.initials: G
authors.lastname: Delle Fave
mesh_terms: D000897:Anti-Ulcer Agents / Q000008:administration & dosage*; D004334:Drug Administration Schedule; D005744:Gastric Acid / Q000378:metabolism; D005753:Gastric Mucosa / Q000187:drug effects*; D005767:Gastrointestinal Diseases / Q000188:drug therapy*; D006635:Histamine H2 Antagonists / Q000008:administration & dosage*; D006801:Humans; D007408:Intestinal Absorption / Q000187:drug effects*; D054328:Proton Pump Inhibitors / Q000008:administration & dosage*; D016032:Randomized Controlled Trials as Topic
chemical_list: D000897:Anti-Ulcer Agents; D006635:Histamine H2 Antagonists; D054328:Proton Pump Inhibitors