title: The effects of gastric bypass surgery on drug absorption and pharmacokinetics.
abstract: BACKGROUND
  Being overweight is widespread in most societies and represents a major health threat. Gastric bypass surgery offers a highly effective mode of treatment for the morbidly obese patients. The procedures cause an alteration in normal gastrointestinal anatomy and physiology, with consequences not only on nutrient absorption, but also possibly on orally administered drugs. Bypass of the acidic environment of the stomach, partial impairment of bile salts-drug interactions and reduced absorptive surface, all create the potential for reduced absorption of drugs.
  
  
  METHODS
  This article provides an overview of the effects of obesity and the most prevalent type of gastric bypass (Roux-en-Y) on pharmacokinetics. Articles for review were searched using Pubmed.
  
  
  CONCLUSIONS
  The absorption of those drugs with known bioavailability issues generally seem to be most affected by bypass surgery. It is important to consider the effect of obesity on pharmacokinetics independent of the bypass procedure, because it leads to a dramatic drop in body mass over a relatively short period of time. This may be associated with reversals in the influence of obesity on drug disposition to characteristics more in line with leaner patients. Drugs will differ in their pharmacokinetic response to surgery, limiting any general conclusions regarding the impact of the surgery on drug disposition.
authors.affiliation: Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, Alberta, Canada. dbrocks@ualberta.ca
authors.forename: Dion R
authors.initials: DR
authors.lastname: Brocks
authors.forename: Mohamed
authors.initials: M
authors.lastname: Ben-Eltriki
authors.forename: Raniah Q
authors.initials: RQ
authors.lastname: Gabr
authors.forename: Raj S
authors.initials: RS
authors.lastname: Padwal
mesh_terms: D000284:Administration, Oral; D000713:Anastomosis, Roux-en-Y / Q000009:adverse effects / Q000379:methods; D001682:Biological Availability; D015390:Gastric Bypass / Q000009:adverse effects* / Q000379:methods*; D006801:Humans; D009767:Obesity, Morbid / Q000601:surgery; D004364:Pharmaceutical Preparations / Q000008:administration & dosage / Q000378:metabolism*; D010599:Pharmacokinetics; D011506:Proteins / Q000378:metabolism; D015431:Weight Loss
chemical_list: D004364:Pharmaceutical Preparations; D011506:Proteins