title: Esophageal irritation due to alendronate sodium tablets: possible mechanisms.
abstract: Animal studies were done using an in vivo dog model to examine the possible mechanism for the esophageal adverse events reported with alendronate sodium tablets. These studies showed that under low pH conditions alendronate sodium can cause esophageal irritation. No esophageal irritation occurred at pH 3.5 or higher where the drug exists primarily as the sodium salt. The animal studies also showed that alendronate sodium can exacerbate preexisting esophageal damage. Exposure of the esophageal mucosa for a prolonged period to alendronate sodium tablet can also cause mild esophageal irritation. These findings suggest that the esophageal irritation in patients taking Fosamax can be from prolonged contact with the tablet, reflux of acidic gastric contents with alendronate sodium, and exacerbation of preexisting esophageal damage. The findings also suggest that other bisphosphonates can cause esophageal injury under similar conditions.
authors.affiliation: Merck Research Laboratories, West Point, Pennsylvania 19486, USA.
authors.forename: C P
authors.initials: CP
authors.lastname: Peter
authors.forename: L K
authors.initials: LK
authors.lastname: Handt
authors.forename: S M
authors.initials: SM
authors.lastname: Smith
mesh_terms: D019386:Alendronate / Q000009:adverse effects*; D000818:Animals; D001862:Bone Resorption / Q000188:drug therapy; D004164:Diphosphonates / Q000009:adverse effects*; D004285:Dogs; D004947:Esophagus / Q000187:drug effects* / Q000473:pathology*; D012968:Etidronic Acid / Q000009:adverse effects / Q000031:analogs & derivatives; D009092:Mucous Membrane / Q000187:drug effects / Q000473:pathology; D000068296:Risedronic Acid
chemical_list: D004164:Diphosphonates; C058651:tiludronic acid; D000068296:Risedronic Acid; D012968:Etidronic Acid; D019386:Alendronate