Pharmacokinetic changes post–bariatric surgery: A scoping review

Abstract

Summary Bariatric surgeries induce structural changes that can alter the absorption of drugs in patients already at risk of polypharmacy. This scoping review aimed to explore pharmacokinetic changes of orally administered drugs in patients post‐bariatric surgery, and assess the quality and level of bias. Electronic databases were searched for articles relating to bariatric surgery and pharmacokinetics published between 1998 and 2019. Pre‐post studies reporting on pharmacokinetic parameters were included, and the Newcastle‐Ottawa Scale was used to assess risk‐of‐bias. A total of 21 studies were included in this review, and changes in absorption were reported in all included studies across 29 drugs. In 11 studies, this change was reported as statistically significant (p<.05), while six reported a nonsignificant change. More drugs exhibited a shorter Tmax and higher Cmax after surgery than otherwise, however changes in AUC were variable. Four studies were assessed as having fair quality while the remainder of the included studies were of good quality and low risk‐of‐bias. Bariatric surgery alters the absorption of drugs and several mechanisms are implicated to be responsible. Short and long‐term monitoring is recommended in patients post‐surgery for clinical changes in response to medications. Future research with a higher number of participants and greater control of variables, such as concurrent medications, malabsorptive disorders, and body composition should be considered.

Impaired dexamethasone resorption in two patients with pseudo‐Cushing after bariatric surgery: Implications for immunosuppressive treatment

“…The extensive endocrine testing performed in the presented cases shows a diminished resorption of orally administered dexamethasone in patients that had bariatric bypass surgery excluding parts of the upper gastrointestinal tract and ileum from resorption. While it is well known that uptake of vitamins 4 and certain drugs 5 are altered after bariatric surgery, to our knowledge there is no data available on the pharmacokinetics of synthetic corticosteroids in these patients. All corticosteroids are lipophilic and have a similar molecular structure.…”

“…In light of the worldwide growing number of bariatric interventions that mounts up to an estimated 252.000 in 2018 for the United States alone, 13 diagnostic tests for the evaluation of the hypothalamic‐pituitary‐adrenal axis need to be revisited in this group of patients and for the different surgical procedures. As previously suggested, 5 future pharmacological studies are required to show bioavailability of essential drugs in patients after bariatric surgery.…”

Optimized In Silico Modeling of Drug Absorption after Gastric Bypass: The Case of Metformin

“…Indeed, data from the literature have been emerging in recent years regarding drug disposition following bariatric surgery [8]. Yet, only few drugs were studied and compared for their pre-vs. post-surgery absorption [9]. One of these drugs is metformin, a first-line treatment for type 2 diabetes, a common comorbidity of obesity.…”

Managing the Unpredictable: Mechanistic Analysis and Clinical Recommendations for Lamotrigine Treatment after Bariatric Surgery

“…Quite a few short- and long-term risks, though, pose a concern among clinicians and patients [ 2 ]. One of the least discussed complications of bariatric surgery involves altered oral drug absorption and bioavailability, potentially leading to efficacy/safety issues of various orally administered medications [ 3 , 4 ]. A few bariatric procedures are commonly available worldwide, including sleeve gastrectomy, some variations of gastric bypass surgeries, notably Roux-en-Y gastric bypass (RYGB) and the newer one-anastomosis gastric bypass (OAGB), and more; and while each procedure is unique in the gastrointestinal anatomic changes that it brings and despite the fact that literature data is mainly available on RYGB, all of these procedures may affect oral drug pharmacokinetics [ 5 , 6 , 7 , 8 , 9 ], with clinically significant ramifications.…”