Drug absorption in bariatric surgery patients: A narrative review

Full-dose rivaroxaban in patients with a history of bariatric surgery: bridging the knowledge gap through a phase 1 study

BACKGROUND

Bariatric surgery (BS) induces significant changes in gastrointestinal anatomy, potentially influencing the pharmacokinetics of orally administered drugs such as rivaroxaban.

OBJECTIVES

This phase 1 study aimed to assess the pharmacokinetics and safety of full-dose rivaroxaban in post-BS patients.

METHODS

The ABSORB (Rivaroxaban Pharmacokinetics and Pharmacodynamics After Bariatric Surgery and in Morbid Obesity) study was a single-center, nonrandomized, multiple-dose, parallel-design bioequivalence trial. Adult patients with stable weight after Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG) were compared with subjects with class III obesity and healthy controls. Participants received 20 mg of rivaroxaban daily for 8 days.

RESULTS

Post-BS patients exhibited altered rivaroxaban pharmacokinetics, suggesting reduced absorption. Mean area under the concentration-time curve from time 0 to 24 hours after the first dose (RYGB, 1806.8 ng.h/mL; SG, 1648.9 ng.h/mL) was lower compared with that in controls (1893.5 ng.h/mL). At steady state, the area under the concentration-time curve values remained lower in BS groups (RYGB, 2129.9 ng.h/mL; SG, 1946.4 ng.h/mL) than in controls (2224.8 ng.h/mL). The maximum concentration after the first dose was lower in post-RYGB subjects (214.9 ng/mL) than in controls (264.1 ng/mL). This difference was less pronounced at steady state (RYGB, 256.9 ng/mL vs controls, 288.8 ng/mL). Neither BS group met bioequivalence criteria compared with controls, whereas the group with class III obesity met bioequivalence criteria compared with controls at steady state.

CONCLUSION

Rivaroxaban displayed minor pharmacokinetic variations in post-BS patients. Given reported interindividual variability in the general population, these variations are unlikely to be of clinical significance. Our findings support rivaroxaban use in BS patients, emphasizing the need for further research in this area.

Molecular Mechanisms Affecting Statin Pharmacokinetics after Bariatric Surgery

According to recent data, one in eight people in the world struggle with obesity. Obesity management is increasingly dependent on bariatric surgical interventions, as the combination of lifestyle modifications and pharmacotherapy could have a modest long-term effect. Surgery is recommended only for individuals whose body mass index (BMI) ≥ 40 kg/m2 and ≥ 35 kg/m2 in the presence of weight-related comorbidities. The most commonly performed procedures are sleeve gastrectomy and roux-en-Y gastric bypass. Pharmacokinetic and pharmacodynamic alterations occur as a result of the anatomical and physiological changes caused by surgery, which further differ depending on physicochemical drug factors and factors related to the dosage form. The following modifications are distinguished based on the type of bariatric surgery performed. Most bariatric patients have accompanying comorbidities, including dyslipidemia treated with hydroxymethylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors or statins. Significant improvements in the lipid profile are observed early in the postoperative period. The data reported in this review on statin pharmacokinetic alterations have demonstrated substantial inter- and intravariability, making it difficult to adopt clear guidelines. Based on the current literature review, reducing the statin dose to the lowest effective with continuous monitoring is considered an optimal approach in clinical practice.

Varying concentrations of tyrosine kinase inhibitors in chronic myeloid leukemia patients following bariatric surgery: a case series

Bariatric surgery is increasingly performed to treat severe obesity. As a result of anatomical and physiological changes in the gastrointestinal tract, the pharmacokinetics (PK) of oral drugs can be altered, affecting their efficacy and safety. This includes the class of tyrosine kinase inhibitors (TKIs) which are used to treat chronic myeloid leukemia (CML). This case series describes the clinical course of four CML cases with a history of bariatric surgery. The patients used various TKIs (nilotinib, dasatinib, bosutinib, ponatinib, and imatinib) for which 15 drug levels were measured. The measured TKI concentrations were in part subtherapeutic, and highly variable when compared to mean levels measured in the general population. Multiple drug levels were measured in these patients, as the clinicians were aware of the possible impact of bariatric surgery. The drug levels were used as additional input for clinical decision-making. All four patients required TKI switches and/or dose modifications to achieve an effective and tolerable treatment. Eventually, adequate clinical and molecular remissions were achieved in all cases. In summary, TKI concentrations of patients undergoing bariatric surgery may be subtherapeutic. Moreover, there is substantial interindividual and intraindividual variation, which may be explained by the complex interference of bariatric surgery and associated weight loss. For clinical practice, therapeutic drug monitoring is advised in patients with a history of bariatric surgery in case of suboptimal response or loss of response.

Medication and supplement pharmacokinetic changes following bariatric surgery: A systematic review and meta-analysis

OBJECTIVES

To evaluate the impact of bariatric surgery on the pharmacokinetic (PK) parameters of orally administered medications and supplements.

METHODS

Systematic searches of bibliographic databases were conducted to identify studies. Pooled effect estimates from different surgical procedures were calculated using a random-effects model.

RESULTS

Quantitative data were synthesized from 58 studies including a total of 1985 participants. Whilst 40 medications and 6 supplements were evaluated across these studies, heterogeneity and missing information reduced the scope of the meta-analysis to the following medications and supplements: atorvastatin, paracetamol, omeprazole, midazolam, vitamin D, calcium, zinc, and iron supplements. There were no significant differences in PK parameters post-surgery for the drugs atorvastatin and omeprazole, and supplements calcium, ferritin, and zinc supplements. Paracetamol showed reduced clearance (mean difference [MD] = -15.56 L/hr, p = 0.0002, I2 = 67%), increased maximal concentration (MD = 6.90 μg/ml, p = 0.006, I2 = 92%) and increased terminal elimination half-life (MD = 0.49 hr, p < 0.0001, I2 = 3%) post-surgery. The remaining 36 medications and 2 supplements were included in a systematic review. Overall, 18 of the 53 drugs and supplements showed post-operative changes in PK parameters.

CONCLUSION

This study demonstrates heterogeneity in practice and could not reach conclusive findings for most PK parameters. Prospective studies are needed to inform best practice and enhance patient healthcare and safety following bariatric surgery.

Reduced Bioavailability of Antidepressants for the Management of Generalized Anxiety Disorder Following Bariatric Surgery: A Case Study

Bariatric surgery is a commonly performed procedure for patients who have failed to achieve weight loss through medical and lifestyle interventions. However, the altered gastrointestinal anatomy resulting from the surgery can significantly impact the bioavailability of antidepressants in patients with generalized anxiety disorder, potentially leading to uncontrolled anxiety symptoms. This case report describes a patient with generalized anxiety disorder who underwent Roux-en-Y gastric bypass surgery and subsequently experienced increased anxiety symptoms due to poor antidepressant bioavailability. The patient's medication was adjusted to a sublingual formulation, resulting in improved anxiety control and reduced side effects. Healthcare providers should be aware of the potential impact of bariatric surgery on medication absorption and closely monitor patients with generalized anxiety disorder for potential psychiatric medication-related complications postoperatively. The use of alternative routes of administration, such as sublingual medication, may be beneficial in improving drug bioavailability and managing anxiety symptoms. Creating awareness in primary care offices about poor drug absorption and using alternatives such as the sublingual route of administration to achieve optimal systemic delivery requires a multifaceted approach involving education and training for healthcare providers as well as patient education to ensure they are informed and engaged in their own care. By implementing these strategies, primary care providers can improve patient outcomes and prevent unnecessary referrals to specialists.

Multiple micronutrient deficiencies as a long-term complication of bariatric surgery

Micronutrient deficiencies may develop as a long-term complication of bariatric surgery due to alteration of gut anatomy and disruption of normal gut absorption. Inadequate repletion of essential vitamin and mineral deficiencies can lead to multisystem dysfunction. We present a case of a woman in her 50s, with a history of Roux-en-Y gastric bypass over 10 years ago, who presented with generalised weakness and a diffuse desquamating rash. A punch biopsy performed was compatible with nutritional deficiency. Labs revealed low levels of micronutrients A, B1, B6, C, E, zinc and copper. The patient received intravenous micronutrients and an oral regimen, which improved her symptoms. Unfortunately, the patient died from cardiac arrest secondary to pulmonary oedema. This report highlights the importance of high suspicion of micronutrient deficiency in patients with a history of bariatric surgery and maintaining lifelong nutritional follow-up.

The Effects of Bariatric Surgery on Pharmacokinetics of Drugs: a Review of Current Evidence

PURPOSE OF REVIEW

Obesity constitutes a major public health concern and has been recognized as an epidemic. To date, bariatric surgery remains the most effective way for substantial long-lasting weight loss in severe obesity. The purpose of this review is to summarize how the pharmacokinetics of drugs are affected by the most common types of bariatric surgery, i.e., Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG).

RECENT FINDINGS

Limited data are available regarding the changes in pharmacokinetics of drugs after bariatric surgery. The lack of existing guidelines may lead patients to experience drug toxicity or therapeutic undertreatment. Pharmacokinetic parameters that need to be taken into consideration postoperatively include gastric motility, gastric volume, pH, surface area, bile secretions, carrier proteins, and first-pass metabolism. For drugs with a narrow therapeutic index, other factors need to be monitored closely, including plasma drug levels, patients' clinical outcomes, and laboratory markers. Patients should be followed up frequently and treated in accordance with their response to the drug therapy. Bariatric surgery may affect the pharmacokinetics of various drugs, due to the resultant anatomical changes and the substantial weight loss. Therefore, there is a need to identify those potential changes and adjust patients' medication doses in order to achieve higher efficacy and avoid toxicity.

Selective COX-2 inhibitors after bariatric surgery: Celecoxib, etoricoxib and etodolac post-bariatric solubility/dissolution and pharmacokinetics

Anatomical/physiological gastrointestinal changes after bariatric surgery may influence the fate of orally administered drugs.Since non-selective NSAIDs are not well-tolerated post-surgery, selective cyclooxygenase-2 (COX-2) inhibitors may be important for these patients. In this work we investigated celecoxib, etoricoxib and etodolac, for impaired post-bariatric solubility/dissolution and absorption. Solubility was studied in-vitro, and ex-vivoin aspirated gastric contents from patients pre- vs. post-surgery. Dissolution was studied in conditions simulating pre- vs. post-surgery stomach. Finally, the experimental solubility data were used in physiologically-based biopharmaceutics model (PBBM) (GastroPlus®) to simulate pre- vs. post-surgery celecoxib/etoricoxib/etodolac pharmacokinetic (PK) profiles.For etoricoxib and etodolac (but not celecoxib), pH-dependent solubility was demonstrated: etoricoxib solubility decreased ∼1000-fold, and etodolac solubility increased 120-fold, as pH increased from 1 to 7, which was also confirmed ex-vivo. Hampered etoricoxib dissolution and improved etodolac dissolution post-surgery was revealed. Tablet crushing, clinically recommended after surgery, failed to improve post-bariatric dissolution. PBBM simulations revealed significantly impaired etoricoxib absorption post-surgery across all conditions; for instance, 79% lower Cmax and 53% decreased AUC was simulated post-gastric bypass procedure, after single 120 mg dose. Celecoxib and etodolac maintained unaffected absorption after bariatric surgery.This mechanistically-based analysis suggests to prefer the acidic drug etodolac or the neutral celecoxib as selective COX-2 inhibitors, over the basic drug etoricoxib, after bariatric surgery.

Metabolic Adverse Effects of Psychotropic Drug Therapy: A Systematic Review

This review aimed to investigate the metabolic alterations associated with psychopharmacological treatment of neuropsychiatric disorders, which can significantly impact patients' physical health and overall quality of life. The study utilized the PRISMA methodology and included cross-sectional, retrospective studies, and randomized clinical trials from reputable databases like SCOPUS, CLARIVATE, SCIENCE DIRECT, and PUBMED. Out of the 64 selected studies, various psychotropic drug classes were analyzed, including antidepressants, anticonvulsants, and antipsychotics. Among the antidepressants, such as amitriptyline, Imipramine, and clomipramine, weight gain, constipation, and cardiovascular effects were the most commonly reported metabolic adverse effects. SSRI antidepressants like Fluoxetine, Sertraline, Citalopram, Escitalopram, and Paroxetine exhibited a high prevalence of gastrointestinal and cardiac alterations. Regarding anticonvulsants, valproic acid and Fosphenytoin were associated with adverse reactions such as weight gain and disturbances in appetite and sleep patterns. As for antipsychotics, drugs like Clozapine, Olanzapine, and Risperidone were linked to weight gain, diabetes, and deterioration of the lipid profile. The findings of this review emphasize the importance of continuous monitoring for adverse effects, particularly considering that the metabolic changes caused by psychopharmacological medications may vary depending on the age of the patients. Future research should focus on conducting field studies to further expand knowledge on the metabolic effects of other commonly prescribed psychotropic drugs. Overall, the study highlights the significance of understanding and managing metabolic alterations induced by psychopharmacological treatment to enhance patient care and well-being.

Self-Nanoemulsifying Drug Delivery System-Containing the Poorly Absorbed Drug - Valsartan in Post-Bariatric Surgery

Purpose

Morbid obesity and its related metabolic syndrome are an important health issue. Recently, sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGB) have accounted for the most popular bariatric surgeries. Valsartan (VST) is a common hypertension drug, and nano-carriers can increase its solubility and bioavailability. This study aims to explore the nano-VST formula in bariatric surgery subjects.

Methods

High-fat fed animals were used as obese models. Operations were performed according to a standardized protocol. The drug was administrated by gavage, and blood samples were taken by serial tail vein sampling. Caco-2 cells were used for examining cell viability and drug uptake. A self-nano-emusifying drug delivery system (SNEDDS) formula was composed of sefsol-218, RH-40 and propylene glycol by a specified ratio, while high-performance liquid chromatography (HPLC) was used for determining drug concentrations.

Results

Post-operatively, subjects that underwent RYGB lost more body weight compared to the SG group. The SNEDDS did not exhibit cytotoxicity after adequate dilution, and the cytotoxicity was not related to VST dose. A better cellular uptake of SNEDDS was observed in vitro. The SNEDDS formula achieved a diameter of 84 nm in distilled water and 140 nm in simulated gastric fluid. In obese animals, the maximum serum concentration (C_max) of VST was increased 1.68-folds by SNEDDS. In RYGB with SUS, the C_max was reduced to less than 50% of the obese group. SNEDDS increased the C_max to 3.5 folds higher than SUS and resulted in 3.28-folds higher AUC_0-24 in the RYGB group. Fluorescence imaging also confirmed a stronger signal of SNEDDS in the gastrointestinal mucosa. SNEDDS accumulated a higher drug concentration than suspension alone in the liver of the obese group.

Conclusion

SNEDDS could reverse the VST malabsorption in RYGB. Further studies are mandatory to clarify post-SG change of drug absorption.

Psychosocial considerations in the combined bariatric surgery and organ transplantation population: a review of the overlapping pathologies and outcomes

PURPOSE OF REVIEW

This review highlights the salient data of the psychosocial concerns that influence outcomes of bariatric surgery and organ transplantation.

RECENT FINDINGS

Bariatric surgery has emerged as an important intervention with data supporting substantial and sustained weight loss, enhanced quality of life, remission of obesity-related medical comorbidities, and improved long-term patient and graft survival in transplant patients. Depression, suicide, anxiety, posttraumatic stress disorder, alcohol use, adherence, and psychopharmacology considerations can influence outcomes of both these surgeries.

SUMMARY

Obesity is increasingly prevalent among patients pursuing transplantation surgery, and it is often a factor in why a patient needs a transplant. However, obesity can be a barrier to receiving a transplant, with many centers implementing BMI criteria for surgery. Furthermore, obesity and obesity-related comorbidities after transplant can cause poor outcomes. In this context, many transplant centers have created programs that incorporate interventions (such as bariatric surgery) that target obesity in transplant candidates. A presurgery psychosocial assessment is an integral (and required) part of the process towards receiving a bariatric surgery and/or a transplantation surgery. When conducting a dual (bariatric and transplantation surgery) psychosocial assessment, it is prudent to understand the overlap and differentiation of specific psychosocial components that influence outcomes in these procedures.