What is the effect on drug absorption after a duodenal switch (Biliopancreatic Diversion with Duodenal Switch, BPD/DS) procedure?

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Last updated: March 21, 2025View editorial policy

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From the Guidelines

Drug absorption after a duodenal switch procedure is significantly altered, requiring careful consideration of medication formulation and monitoring to minimize adverse effects on morbidity, mortality, and quality of life. The duodenal switch procedure, also known as Biliopancreatic Diversion with Duodenal Switch (BPD/DS), alters the anatomy of the small intestine, reducing the absorptive surface area and bypassing the duodenum and proximal jejunum where many nutrients and medications are normally absorbed 1. This can lead to decreased absorption of fat-soluble vitamins (A, D, E, K), calcium, iron, zinc, and certain medications. For optimal medication management, water-soluble, immediate-release formulations are preferred over extended-release or enteric-coated preparations, as sustained- and delayed-release medications should be avoided in patients with short bowel syndrome 1. Some key points to consider include:

  • Medications requiring acidic environments for absorption may be less effective due to reduced stomach acid production.
  • Patients should take lifelong vitamin and mineral supplements, including a high-potency multivitamin, calcium citrate, vitamin D3, iron, and vitamin B12.
  • Blood levels of medications with narrow therapeutic windows, such as anticoagulants, anticonvulsants, thyroid hormones, and immunosuppressants, should be monitored closely, and dosages adjusted accordingly 1.
  • Alternative drug delivery methods, such as liquids or topical formulations, may be necessary for certain medications 1.
  • The solution to a lack of clinical response to a drug may involve escalating the dose, changing the dosing schedule or frequency, or changing to a different drug formulation or route of administration 1. Given the most recent and highest quality evidence, patients undergoing a duodenal switch procedure should be closely monitored for potential malabsorption and adjusted medication regimens to ensure optimal outcomes and minimize adverse effects on morbidity, mortality, and quality of life 1.

From the Research

Effect of Duodenal Switch on Drug Absorption

  • The duodenal switch procedure, also known as Biliopancreatic Diversion with Duodenal Switch (BPD/DS), can affect drug absorption due to changes in the gastrointestinal tract 2.
  • A case report suggests that the duodenal switch procedure may lead to malabsorption of lurasidone, a second-generation antipsychotic, resulting in incomplete response to therapy 2.
  • Another study found that bariatric surgery, including duodenal switch, can alter the absorption of orally administered medications in an unpredictable manner, highlighting the need for close monitoring of therapeutic and toxic effects 3.
  • A systematic review of drug absorption following bariatric surgery found that the effect of surgery on drug absorption appears to be drug-specific, with some medications exhibiting diminished absorption after certain types of bariatric procedures, including jejunoileal bypass and gastric bypass/gastroplasty, but not biliopancreatic diversion 4.
  • However, the review also noted that drugs that are intrinsically poorly absorbed, highly lipophilic, and/or undergo enterohepatic recirculation may be more susceptible to malabsorption after bariatric surgery, including duodenal switch 4.

Factors Influencing Drug Absorption

  • The location and extent of intestinal resection or bypass can influence drug absorption, with some medications being more affected than others 5.
  • The presence of a colon in continuity may also impact drug bioavailability, as it can contribute to the absorption of certain medications 5.
  • Individualized dosing and therapeutic drug monitoring may be necessary to achieve therapeutic efficacy in patients who have undergone duodenal switch or other bariatric procedures 5, 4.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Impaired oral absorption of methylphenidate after Roux-en-Y gastric bypass.

Surgery for obesity and related diseases : official journal of the American Society for Bariatric Surgery, 2017

Research

A systematic review of drug absorption following bariatric surgery and its theoretical implications.

Obesity reviews : an official journal of the International Association for the Study of Obesity, 2010

Research

Changes of Drug Pharmacokinetics in Patients with Short Bowel Syndrome: A Systematic Review.

European journal of drug metabolism and pharmacokinetics, 2021

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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