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Bariatric Procedures. A. Roux-en-Y bypass involves creation of a small gastric pouch from the newly isolated stomach and proximal small bowel that is excluded from gastric transfer. The pouch is anastomosed to the small intestine, forming the Roux limb. Food enters the pouch, moves through Roux limb and then reaches the common channel where pancreatic fluids and bile have entered from the bypassed bilipancreatic limb. B, C. Banding and gastric sleeve are purely restrictive procedures with bowel beyond the stomach remaining intact. D. BPD/DS involves creation of a gastric sleeve along with and resection of the majority of duodenum beyond the most proximal portion to the stomach. The distal segment of small intestine is then connected to the stomach and the bypassed duodenal portion (biliopancreatic limb) anastomosed to the last portion of the small intestine, forming a common channel, often shorter and resulting in greater malabsorption than that with Roux-en-Y. From Roust LR & DiBaise JK. Nutrient deficiencies prior to bariatric surgery. Curr Opin Clin Nutr Metab Care. 2017 Mar;20(2):138-144; used with permission of Mayo Foundation for Medical Education and Research, all rights reserved.
Source publication
Healthcare professionals are encountering an increasing number of patients who have undergone bariatric surgeries. Antiseizure medications (ASMs) have a narrow therapeutic window, and patients with malabsorptive states receiving ASMs present a complex situation as the pharmacokinetics of these drugs have only been studied in patients with a normal...
Context in source publication
Context 1
... to the common channel where food comes into contact with pancreatic fluids and bile that enter the common channel via the bypassed biliopancreatic limb. This common channel is typically longer in RYBG compared to BPD, and therefore the latter results in more malabsorption of fats and nutritents [9][10][11]. These procedures are illustrated in Fig. ...
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Objective
Human white adipose tissue (AT) is a metabolically active organ with distinct depot-specific functions. Despite their locations close to the gastrointestinal tract, mesenteric AT and epiploic AT (epiAT) have only scarcely been investigated. Here, we aim to characterise these ATs in-depth and estimate their contribution to alterations in w...
Citations
... Based on pharmacokinetic properties, levetiracetam (BCS class I, T max 3-4.5 h) and topiramate (BCS class I, T max 1.5-4 h for IR) seem to be preferable for their hydrophilicity, absence of intestinal metabolism, and enterohepatic circulation and poor affinity to P-glycoprotein. On the other hand, carbamazepine (BCS class II, T max 4-5 h for IR), oxcarbazepine (BCS class II, T max 3-13 h for IR), phenytoin (BCS class II, T max 4-12 h), and valproic acid (BCS class II, T max 1-3 h) are lipophilic, are metabolized by the intestinal cells, and undergo enterohepatic circulation, and apart from valproic acid, they are also P-glycoprotein substrates and CYP 3A4 and P-gp autoinducers which may lead large variability in absorption after BS [61]. Porat et al. described a decrease in carbamazepine levels in 4 out of 8 patients after SG, all using a controlled-release formulation. ...
... After this period the frequency of measurements should be adjusted according to the individual fluctuations in plasmatic levels. Extended-release formulations should be avoided during the first 6 months [61]. Therapeutic drug monitoring of anticonvulsants plays a key role in these patients. ...
Purpose of Review
Oral drug absorption after bariatric surgery is likely to be altered, but the impact of different bariatric surgery procedures on individual drugs is not uniform. The aim of this article is to describe factors influencing the bioavailability of orally administered drugs after bariatric surgery and to provide readers with practical recommendations for drug dosing. We also discuss the medications that may be harmful after bariatric surgery.
Recent Findings
The fundamental factors for enteral drug absorption are the production of gastric acid; the preserved length of the intestine, i.e., the size of the absorption surface and/or the preserved enterohepatic circulation; and the length of common loop where food and drugs are mixed with digestive enzymes and bile acids. Bypassing of metabolizing enzymes or efflux pumps and changes in intestinal motility can also play an important role. Significant changes of drug absorption early after the anatomic alteration may also be gradually ameliorated due to gradual intestinal adaptation. The most affected drugs are those with low or variable bioavailability and those undergoing enterohepatic circulation. Attention should also be paid to oral drug formulations, especially in the early postoperative period, when immediate-release and liquid formulations are preferred.
Summary
The changes in oral bioavailability are especially clinically meaningful in patients treated with drugs possessing narrow therapeutic index (e.g., oral anticoagulants, levothyroxine, and anticonvulsants) or in acute conditions (e.g., anti-infectives); nevertheless, it may also influence the therapeutic value of chronic therapy (e.g., antidepressants. antihypertensives, antiplatelets, statins, PPIs, contraceptives, and analgesics); therapeutic effect of chronic therapy is further influenced by pharmacokinetic alterations resulting from weight loss. Therapeutic drug monitoring, periodical clinical evaluation, and adequate dose adjustments are necessary. Due to safety reasons, patients should avoid oral bisphosphonates, regular use of non-steroidal anti-inflammatory drugs, and, if possible, corticosteroids after bariatric surgery.
... -12 months and 1.5 years: the total and free levels were within therapeutic range (52-62 mg/L and 5 mg/L respectively.) [37] Content courtesy of Springer Nature, terms of use apply. Rights reserved. ...
Sparse information is available on pharmacokinetic changes of drugs over time after bariatric surgery. By reviewing the literature on the short- and long-term pharmacokinetic changes of drugs, several patterns were identified for 39 drugs. No relevant pharmacokinetic changes were identified for roughly a third of the drugs. Of the remaining drugs, levels were variable and partly unpredictable shortly after the surgery. In the long term, most of the drug levels remain altered, but in some cases they returned to preoperative values. Based on the changes and the efficacy-safety balance of each drug, clinicians may need to perform additional clinical monitoring for specific drugs, including measuring drug levels. This review provides suggestions for clinicians and pharmacists for specific time-dependent drug dosing advice.
Supplementary Information
The online version contains supplementary material available at 10.1007/s11695-023-06770-5.
... The negative impact that bariatric surgery has on intestinal absorption could justify the lower weight loss potency. Topiramate, on the other hand, appears to be safely absorbed [4]. ...
Background:
Bariatric surgery is the most efficient treatment for obesity. However, in some cases, weight regain can occur. Currently, it is unknown the best antiobesity medication (AOM) for such clinical situation. This study aims to evaluate the effect of AOM in patients with weight regain after bariatric surgery.
Methods:
A retrospective cohort study from December 2010 to July 2019 with patients submitted to bariatric surgery that had weight regain and received AOM for at least 2 years.
Results:
Of 96 patients that had weight regain in the analyzed period and received AOM, 16 were excluded from the analysis due to non-compliance (n = 7), treatment failure (n = 5), intolerable side effects with all available AOM (n = 2), or interaction with other medications (n = 2). Eighty patients were included in the analysis. The mean age was 59.0 ± 10.1 years, 88.8% were female, 91.2% white, and most of them were submitted to gastric bypass (87.6%). The mean preoperative and nadir weight after surgery were 127.9 ± 25.5 kg and 84.7 ± 22.8 kg, respectively. At the initiation of AOM, the mean baseline weight was 99.4 ± 23.1 kg. After 2 years of follow-up, there was significant weight loss in the groups treated with topiramate-alone (- 3.2 kg), topiramate plus sibutramine (- 6.1kg), and orlistat-alone or in combination (- 3.9kg). No statistical difference was observed in the sibutramine-alone group.
Conclusion:
Topiramate (alone or associated with sibutramine) and orlistat (alone or in combination) promoted significant weight loss after 2 years of use in patients submitted to bariatric surgery with weight regain.
... Due to this reason, therapeutic drug monitoring is a common practice with some anticonvulsants [11]. In the context of bariatric surgery, these orally administered drugs may require extra care due to possible alterations in the mechanisms responsible for their absorption and disposition in the body [12]. In fact, some of these mechanisms are associated with increased drug exposure, while others may lead to decreased plasma drug levels [13]. ...
... Realizing the need for extra care when prescribing to a patient after bariatric surgery is of importance, given the unpredictable effects of the surgery. While only older antiepileptics are routinely monitored, therapeutic drug monitoring of newer antiepileptics is also warranted after the surgery [12]. Indeed, lamotrigine should be monitored, both for potentially altered trough plasma drug levels and for clinical signs of safety issues/treatment failure. ...
... Especially in the first few months after bariatric surgery, lamotrigine levels should be checked frequently. Preferably, lamotrigine blood levels can also be measured shortly before the surgery to discern basal effective levels that should then be aimed after the operation [12]. Involvement of clinical pharmacists as advisors in the drug treatment is beneficial for both surgeons and patients. ...
Bariatric surgery may alter the absorption and overall bioavailability of oral drugs. Lamotrigine is a major antiepileptic and mood stabilizer, that its use after bariatric surgery has not yet been studied. In this article, we provide a thorough mechanistic analysis of the effects of bariatric surgery on multiple mechanisms important for the absorption, bioavailability and overall pharmacokinetics of lamotrigine. Attributable to its pharmacokinetic properties and drug characteristics, the use of lamotrigine after bariatric surgery may be challenging. The complex situation in which some mechanisms may lead to increased drug exposure (e.g., decreased metabolism, weight loss) while others to its decrease (e.g., hampered dissolution/solubility, decreased gastric volume), may result in lowered, unchanged, or enhanced lamotrigine plasma levels after the surgery. We conclude with a set of clinical recommendations for lamotrigine treatment after bariatric surgery, aiming to allow better patient care, and emphasizing the extra caution that needs to be taken with these patients.
Bariatric surgery modifies the anatomy and physiology of the gastrointestinal tract. Carbamazepine (CBZ) is an anticonvulsant with multiple neuropsychiatric indications. Given CBZ physicochemical properties and narrow therapeutic index, bariatric surgery may potentially introduce clinically significant changes in CBZ oral absorption and bioavailability. In this communication, we describe eight patients undergoing sleeve gastrectomy (SG) and treated with CBZ, including therapeutic drug monitoring (TDM) and dosage adjustments at different timeframes before vs. after the surgery (< 3, 4–6, and 7–12 months post-SG), as well as clinical outcomes. We then provide a review of the available literature on CBZ therapy among bariatric patients, concluding with a mechanistic analysis of the results. Four of the eight patients presented with decreased post-SG CBZ levels, and two of them also experienced significant worsening of their previously well-controlled disease. Overall, altered CBZ levels are likely for at least a year after SG. Clinical recommendations include consultation with a clinical pharmacist, careful clinical monitoring, and periodic TDM after (vs. before) the bariatric surgery.
