The effect of gastric bypass on the pharmacokinetics of serotonin reuptake inhibitors

Pharmacotherapy of carbamazepine-treated patient after bariatric surgery: a complex interplay between altered absorption and drug-drug interactions

Changes in absorption and bioavailability of drugs have been described after bariatric surgery, especially shortly after the procedure. When a significant drug-drug interaction also occurs, it is difficult to predict the final combined effect of the surgery and the interaction. In this article, we present a case report of a patient with chronic psychiatric poly-medication including carbamazepine, a strong cytochrome P450 3A4 (CYP3A4) inducer. Significant changes in serum drug concentrations were observed during the 6 months after the surgery, including increased levels of quetiapine and trazodone, that cannot be attributed to the post-surgical alteration of absorption from the gastrointestinal tract. The influence of fluctuating carbamazepine levels on concomitant medication seemed to outweigh the effect of reduced absorption after surgery. This report highlights the need for careful pre-surgical evaluation of the patient's pharmacotherapy and pre- and post-operative therapeutic drug monitoring to prevent destabilisation of chronic conditions.

Clinical Guidance for Dosing and Monitoring Oral Antihormonal Drugs in Patients with Breast Cancer After Roux-en-Y Gastric Bypass

ABSTRACT

Obesity is associated with an increased risk of cancers, such as breast cancer. Roux-en-Y gastric bypass (RYGB) is a common surgical intervention used to induce weight loss, reduce comorbidities, and improve overall survival. Due to alterations in the gastrointestinal tract, RYGB is associated with changes in oral drug disposition, which can affect treatment outcomes. Oral antihormonal agents were monitored in 9 patients who previously underwent RYGB. The results of therapeutic drug monitoring and estradiol concentrations were analyzed, and a review of the relevant literature was performed. As only 1 of the 6 patients prescribed tamoxifen achieved a therapeutic endoxifen concentration with the standard dose of 20 mg/d, a higher starting dose of 40 mg/d was recommended to increase the probability of attaining a therapeutic plasma concentration. All patients with decreased CYP2D6 metabolic activity could not achieve therapeutic plasma concentrations; therefore, CYP2D6 genotyping was recommended before the initiation of tamoxifen therapy to identify patients who should be switched to aromatase inhibitors. Anastrozole and letrozole exposure in patients who underwent RYGB patients appeared sufficient, with no dose adjustment required. However, until more data become available, monitoring aromatase inhibitor efficacy is recommended. Monitoring the drug concentrations is a viable option; however, only indicative data on therapeutic drug monitoring are available. Therefore, estradiol concentrations should be measured.

Changes in Serum Concentration of Antidepressants After Bariatric Surgery and Recommendations for Postbariatric Surgery Antidepressant Therapy

BACKGROUND

Bariatric surgery affects the absorption of medications including antidepressants, but data regarding these effects are limited.

OBJECTIVES

Our objectives were to review publicly available data regarding changes in antidepressant serum concentration following bariatric surgery in order to develop medication dosing recommendations in this patient population.

METHODS

A comprehensive literature review was performed utilizing key search terms in Pubmed. Additional data were retrieved from the Food and Drug Administration and DrugBank Online resources.

RESULTS

A total of twelve published articles were included in addition to the publicly available data from the Food and Drug Administration and DrugBank. The serum concentration of antidepressants following bariatric surgery demonstrated considerable variability between and within drug classes due to unique pharmacokinetic features, drug preparation, and formulation. Recommendations were developed from published data regarding changes in serum concentration and drug-specific pharmacokinetic data.

CONCLUSIONS

To our knowledge, this is the first study to propose medication dose-adjustment recommendations for patients on antidepressants undergoing bariatric surgery. We were limited by the relatively small amount of data available and recommend monitoring patients and use of clinical judgment along with this guidance.

Bioavailability of Orally Administered Drugs After Bariatric Surgery

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. 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.

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.

Effects of Sleeve Gastrectomy and Roux-en-Y Gastric Bypass on Escitalopram Pharmacokinetics: A Cohort Study

BACKGROUND

Changes in the gastrointestinal physiology after bariatric surgery may affect the pharmacokinetics of medications. Data on the impact of different surgical techniques on the pharmacokinetics of commonly prescribed antidepressants such as escitalopram are limited.

METHODS

This case-only prospective study investigated escitalopram-treated patients who underwent bariatric surgery at hospitals in Central Norway. Escitalopram concentrations were assessed using serial blood samples obtained during a dose interval of 24 hours preoperatively and at 1, 6, and 12 months, postoperatively. The primary outcomes were changes in the area under the time-concentration curve (AUC 0-24 ) with secondary outcomes, including full pharmacokinetic profiling. We performed repeated-measures analysis of variance for the AUC 0-24 and secondary outcomes.

RESULTS

Escitalopram-treated obese patients who underwent sleeve gastrectomy (n = 5) and Roux-en-Y gastric bypass (n = 4) were included. Compared with preoperative baseline, dose-adjusted AUC 0-24 values were within ±20% at all time points, postoperatively in the sleeve gastrectomy and oux-en-Y gastric bypass groups, with the largest changes occurring 1 month postoperatively (+14.5 and +17.2%, respectively). No statistically significant changes in any pharmacokinetic variables over time were reported; however, there was a trend toward increased maximum concentrations after surgery ( P = 0.069).

CONCLUSIONS

Our findings suggest that bariatric surgery has no systematic effect on the pharmacokinetics of escitalopram. However, because of the substantial interindividual variation, therapeutic drug monitoring can be considered to guide postoperative dose adjustments.

Suicide attempts after bariatric surgery: comparison to a nonsurgical cohort of individuals with severe obesity

BACKGROUND

The rate of suicide is higher among individuals following bariatric surgery compared with the general population; however, it is not clear whether risk is associated with bariatric surgery beyond having severe obesity.

OBJECTIVE

To compare the risk of a suicide attempt among those who had bariatric surgery versus a nonsurgical cohort with severe obesity.

SETTING

Aggregate count data were collected from 5 healthcare systems.

METHODS

Individuals were identified in the surgical cohort if they underwent bariatric surgery between 2009 and 2017 (n = 35,522) and then were compared with a cohort of individuals with severe obesity who never had bariatric surgery (n = 691,752). Suicide attempts were identified after study enrollment date using International Classification of Diseases, Ninth and Tenth Editions (ICD-9 and ICD-10) diagnosis codes from 2009 to 2021.

RESULTS

The relative risk of a suicide attempt was 64% higher in the cohort with bariatric surgery than that of the nonsurgical cohort (2.2% versus 1.3%; relative risk = 1.64; 95% CI, 1.53-1.76). Within the cohort with bariatric surgery, suicide attempts were more common among the 18- to 39-year age group (P < .001), women (P = .002), Hawaiian-Pacific Islanders (P < .001), those with Medicaid insurance (P < .001), and those with a documented mental health condition at baseline (in the previous 2 years; P < .001).

CONCLUSIONS

The relative risk of suicide attempts was higher among those who underwent bariatric surgery compared with a nonsurgical cohort, though absolute risk remained low. Providers should be aware of this increased risk. Screening for suicide risk after bariatric surgery may be useful to identify high-risk individuals.

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.

Impact of Bariatric Surgery in the Short and Long Term: A Need for Time-Dependent Dosing of Drugs

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.

Plasma concentrations of SSRI/SNRI after bariatric surgery and the effects on depressive symptoms

Background

Depression and treatment with antidepressants SSRI/SNRI are common in people with morbid obesity who are candidates for bariatric surgery. There is few and inconsistent data about the postoperative plasma concentrations of SSRI/SNRI. The aims of our study were to provide comprehensive data about the postoperative bioavailability of SSRI/SNRI, and the clinical effects on depressive symptoms.

Methods

Prospective multicenter study including 63 patients with morbid obesity and therapy with fixed doses of SSRI/SNRI: participants filled the Beck Depression Inventory (BDI) questionnaire, and plasma levels of SSRI/SNRI were measured by HPLC, preoperatively (T0), and 4 weeks (T1) and 6 months (T2) postoperatively.

Results

The plasma concentrations of SSRI/SNRI dropped significantly in the bariatric surgery group from T0 to T2 by 24.7% (95% confidence interval [CI], -36.8 to -16.6, p = 0.0027): from T0 to T1 by 10.5% (95% 17 CI, -22.7 to -2.3; p = 0.016), and from T1 to T2 by 12.8% (95% CI, -29.3 to 3.5, p = 0.123), respectively.There was no significant change in the BDI score during follow-up (-2.9, 95% CI, -7.4 to 1.0; p = 0.13).The clinical outcome with respect to SSRI/SNRI plasma concentrations, weight change, and change of BDI score were similar in the subgroups undergoing gastric bypass surgery and sleeve gastrectomy, respectively. In the conservative group the plasma concentrations of SSRI/SNRI remained unchanged throughout the 6 months follow-up (-14.7, 95% CI, -32.6 to 1.7; p = 0.076).

Conclusion

In patients undergoing bariatric surgery plasma concentrations of SSRI/SNRI decrease significantly by about 25% mainly during the first 4 weeks postoperatively with wide individual variation, but without correlation to the severity of depression or weight loss.

Lower sertraline plasma concentration in patients co-medicated with clozapine-Implications for pharmacological augmentation strategies in schizophrenia

Augmentation of antipsychotic treatment with antidepressants represents a common and beneficial treatment strategy in patients suffering from schizophrenia. Combining clozapine and the selective serotonin reuptake inhibitor (SSRI) sertraline represents a clinically important strategy in patients with therapy-resistant schizophrenia, but there is limited knowledge about mutual pharmacokinetic interactions. In the present study, we assessed the impact of clozapine on sertraline plasma concentrations. Based on a therapeutic drug monitoring (TDM) database, sertraline plasma concentrations were compared between two groups: patients receiving a combined treatment with sertraline and clozapine (N = 15) and a matched control group receiving sertraline but no clozapine (N = 17). Group differences with respect to raw and dose-adjusted concentrations were assessed using nonparametric tests. Comedication with clozapine was associated with 67% lower median sertraline plasma concentrations (16 vs. 48 ng/mL; p = .022) and 28% lower median dose-adjusted plasma concentrations (C/D; 0.21 vs. 0.29 (ng/mL)/(mg/day); p = .049) as compared to the control group. Scatter plots revealed a complex relationship between the dosage of clozapine and dose-adjusted sertraline concentrations composed of an initial decrease at clozapine doses below 300 mg, an increase between 300 and 600 mg and a final decrease at 800 mg which was best modeled by a third order polynomial term. Cotreatment with clozapine may lead to reduced sertraline plasma concentrations which may be explained by clozapine-induced gastrointestinal hypo-mobility already present at low doses and cytochrome P450 3A4 inducing properties at high clozapine doses. For this drug combination, clinicians should consider TDM to confirm therapeutically effective plasma concentrations of sertraline.

The Influence of a Roux-en-Y Gastric Bypass on Plasma Concentrations of Antidepressants

PURPOSE

Roux-en-Y gastric bypass (RYGB) involves alterations of the gastrointestinal tract resulting in altered absorption. Patients with obesity have a higher prevalence of depression, and antidepressants are often prescribed. Alterations caused by RYGB could modify drug bioavailability and cause potential subtherapeutic plasma concentrations, increasing the risk of depressive relapse. The aim of this study was to describe the evolution of trough drug dose-normalized antidepressant plasma concentrations before and after RYGB.

MATERIALS AND METHODS

This naturalistic prospective case series considers patients with trough plasma concentrations in a 1-year timeframe before and after RYGB. Only antidepressants prescribed to at least three patients were included in the present study.

RESULTS

Thirteen patients (n = 12 females, median age 44 years, median BMI before intervention = 41.3 kg/m²) were included. Two patients were treated concurrently with fluoxetine and trazodone; the remaining patients were all treated with antidepressant monotherapy. Therapeutic drug monitoring (TDM) values for duloxetine (n = 3), escitalopram (n = 4), fluoxetine (n = 4), and trazodone (n = 4) before (median 4.7 weeks) and after (median 21.3 weeks) RYGB intervention were analyzed. Compared to preintervention, median [interquartile range] decreases in dose-normalized trough plasma concentrations for duloxetine (33% [- 47; - 23]), escitalopram (43% [- 51; - 31]), fluoxetine (9% [- 20; 0.2]), and trazodone (16% [- 29; 0.3]) were observed.

CONCLUSION

This study shows a decrease in plasma antidepressant concentrations following RYGB. TDM before and after RYGB, in addition to close monitoring of psychiatric symptomatology, may help optimize antidepressant treatment after bariatric surgery. These results also highlight the need for prospective studies assessing the clinical evidence available through TDM in these patients.

Consultation-Liaison Case Conference: Psychiatric Care of Patients Who Undergo Bariatric Surgery

We present the case of a 42-year-old female with major depressive disorder who received a Roux-en-Y gastric bypass and subsequently decompensated in her depression symptoms and began newly engaging in problematic alcohol use. Top experts in the consultation-liaison field, specifically bariatric surgery psychiatry, provide guidance for this commonly encountered clinical case based on their experience and a review of the available literature. Key teaching points include the presurgical psychosocial assessment, pertinent perioperative psychopharmacology, and problematic alcohol use after bariatric surgery.

Evaluating the success of American Society of Metabolic and Bariatric Surgery research grants

BACKGROUND

Since 2004 the American Society of Metabolic and Bariatric Surgery (ASMBS) Foundation has funded competitive proposals by ASMBS members that are administered through the ASMBS Research Committee. These grants are intended to further the knowledge in the field of metabolic and bariatric surgery and support the scholarly growth of its members.

OBJECTIVES

The aim of this project was to evaluate the factors associated with grant completion success and barriers encountered by investigators.

SETTING

ASMBS.

METHODS

Members of the ASMBS Research Committee retrospectively reviewed all awarded research grants since 2004. Information captured included research topic, status of awarded grants, and related publications. Further, a web-based survey of grant recipients was administered exploring the perceived factors of successful completion and barriers encountered.

RESULTS

Since 2004, ASMBS members have been awarded 28 research grants funded by the ASMBS Foundation totaling $1,033,000. Fifty-seven percent of awardees responded to the survey. Seventeen projects had been completed at the time of the survey leading to 13 publications, while 11 remain in progress. Seventy percent of non-completed grant recipients indicated that a publication was forthcoming in the next 12 months. Overall, 64% received additional funding. Factors reported to influence successful completion of grants included the effectiveness of the research team, principal investigator (PI) perseverance, PI protected time, institutional support and available resources, and mentorship. Over the last decade, the average time from the award to publication was 2 years.

CONCLUSIONS

The research grants awarded by the AMSBS are successful at producing peer reviewed publications at a high rate and often lead to further funding suggesting that they boost the career of their recipients. The identified factors of success can help guide future applicants and the ASMBS Research Committee during its grant selection process.

Drug absorption in bariatric surgery patients: A narrative review

Background

Despite the increase in the number of bariatric surgeries performed, little is known about the impact of the surgery on drug absorption. Unpredictability is assumed with drugs, given the anatomical changes after surgery.

Objective

To evaluate the impact of bariatric surgery on drug absorption based on the type of procedure performed.

Methods

We conducted a comprehensive literature review searching PubMed/Medline for published studies (from inception to December 2017) that evaluate the use of drugs and the assessment of drug absorption after bariatric surgery. Pharmacokinetic/pharmacodynamic studies, case reports, and observational studies were included in our review.

Results

We found 60 studies addressing drug use after bariatric surgery. Twenty‐eight studies reported a decrease in drug absorption after bariatric surgery while only four studies showed an increase in drug absorption. Unchanged absorption of drugs was seen in 23 studies after the surgery.

Conclusion

The available information shows variations in drug absorption after bariatric surgery. The unpredictability may result from factors related to the patient, drug, and/or type of surgery. Therefore, pharmacists' involvement and close monitoring of patients after bariatric surgery could be effective to avoid sub‐/supratherapeutic responses.

Psychotropic Medications in Metabolic and Bariatric Surgery: Research Updates and Clinical Considerations

PURPOSE OF REVIEW

We review evidence for assessing and monitoring psychotropic medications in metabolic and bariatric surgery (MBS) patients. We describe weight gain side effects, potential perioperative risks, pharmacokinetic changes that occur after MBS, and conclude with clinical recommendations.

RECENT FINDINGS

Research on psychiatric medication use and post-MBS weight outcomes is lacking and inconsistent; however, there is consistent evidence that, though variable, psychiatric medication use is associated with weight gain. Several meta-analyses and reviews provide guidance on lowering risk when appropriate. Perioperative lithium toxicity and SSRI discontinuation syndrome also warrant consideration, as do potential post-operative pharmacokinetic changes. In the absence of data for each psychiatric drug classification, close symptom monitoring and, where appropriate, serum concentration monitoring are recommended. MBS patients are a psychiatrically vulnerable population, and many are on psychiatric medications. Given potential weight/metabolic side effects, perioperative complications, and post-operative pharmacokinetic changes that occur with psychotropic medication use, providers should stay well informed on psychiatric medication management considerations.

Improvement in mood symptoms ​after post-bariatric surgery among people with obesity: A systematic review and meta-analysis

AIMS

We aimed to examine if bariatric surgery was associated with a reduction in the prevalence of depressive and anxiety symptoms among people with obesity.

MATERIALS AND METHODS

We pooled data from 49 studies involving 11,255 people with obesity who underwent bariatric surgery. The study outcomes were the prevalence of depressive and anxiety symptoms among these patients pre- and post-surgery.

RESULTS

There was a significant reduction in body mass index (BMI) post-operatively (pooled d+: -13.3 kg/m² [95% confidence interval [CI] 15.19, -11.47], p < 0.001). The pooled proportion of patients with anxiety symptoms reduced from 24.5% pre-operatively to 16.9% post-operatively, with an odds ratio (OR) of 0.58 (95% CI 0.51, 0.67, p < 0.001). The reduction remained significant in women aged ≥40 years and irrespective of post-operative BMI. There were significant reductions in Hospital Anxiety and Depression Score (HADS) (anxiety component) by 0.64 (pooled d+: -0.64 [95% CI -1.06, -0.22], p = 0.003) and Generalized Anxiety Disorder Assessment-7 score by 0.54 (pooled d+: -0.54 [95% CI -0.64, -0.44], p < 0.001). The pooled proportion of depressive symptoms reduced from 34.7% pre-operatively to 20.4% post-operatively, with an OR of 0.49 (95% CI 0.37, 0.65, p < 0.001). The reduction remained significant irrespective of patient's age and post-operative BMI. There were also significant reductions in HADS score (depressive component) (pooled d+: -1.34 [95% CI -1.93, -0.76], p < 0.001), Beck's Depression Inventory score (pooled d+: -1.04 [95% CI -1.46, -0.63], p < 0.001) and Patient Health Questionnaire-9 score (pooled d+: -1.11 [95% CI -1.21, -1.01], p < 0.001).

CONCLUSION

Bariatric surgery was associated with significant reduction in the prevalence and severity of depressive and anxiety symptoms among people with obesity.

[Contraception in women with obesity]

Obese women are at high risk of unintended pregnancy. In addition, obesity is an important risk factor for venous thromboembolism events and arterial thrombosis. All of these data are to be considered in choosing a contraceptive method for obese women. The metabolic changes and the increased body mass of these women may be the cause of a reduction in the effectiveness of hormonal contraception. The progestin-only contraceptives (progestin only pills and etonogestrel subdermal implant) and the intra-uterine devices are the preferred contraceptive methods in women with obesity. The combined estrogen-progestin contraceptives may be proposed in young obese women without other cardiovascular risk factor. Obesity per se does not seem to increase the risk of failure of most contraceptive methods. Bariatric surgery is a complex situation. Contraception is needed for at least 12 months after surgery. Some bariatric surgery such as bypass can induce gastrointestinal malabsorption. In this situation, all oral contraceptives are not recommended because of a higher risk of failure.

The effect of weight reduction surgery on the efficacy and tolerability of epilepsy pharmacotherapy

BACKGROUND

Bariatric surgery is an increasingly utilized procedure among patients with obesity-related medical complications. The impact of bariatric surgery on seizure frequency and antiseizure drug (ASD) levels are not well described.

METHODS

We conducted a retrospective chart review of adult patients with a history of epilepsy or seizures undergoing bariatric surgery for morbid obesity from September 1997-September 2019. The median follow-up was 60 months [range 9-220 months].

RESULTS

Forty-six patients with a history of seizures were identified (38 female); 44 patients had recurrent and unprovoked seizures. Seventeen sets of pre- and post-surgery drug concentrations from 14 patients were reviewed. The median age at surgery was 44 years (range, 19-68). Thirty-three patients were prescribed ASDs at the time of bariatric surgery (median 1 drug [range, 1-3]). Laparoscopic Roux-en-Y was performed in 40 patients, and sleeve gastrectomy in 6 patients. Median pre-surgery weight was 120.75 kg (range, 71-230) and BMI 44.4 kg/m2 (range, 34-77.6). Six months following surgery the median weight was 89.5 kg (range, 58.2-202) and BMI 34.2 kg/m2 (range, 24.5-61.9). Nine patients (19.6%) had a worsening of seizure control on long-term follow-up (median 60, range 9-220 months) following bariatric surgery, including five (10.8%) who suffered seizures within 6 months of bariatric surgery. Five patients developed ASD-associated side effects following bariatric surgery including irritability in two patients (levetiracetam and phenytoin) and one patient each suffering from somnolence (phenytoin), hyperammonemic encephalopathy (sodium valproate), and nausea and vomiting (carbamazepine). Subtherapeutic post-surgery drug concentrations were identified in 5 patients and supratherapeutic concentrations in one patient. In the initial 6 months following surgery, ASD doses were increased in five patients and reduced in five.

CONCLUSIONS

The majority of patients with epilepsy who undergo bariatric surgery have no change in seizure frequency. However, a significant minority of patients may experience medication side effects or an increase in seizure tendency due to the impact of bariatric surgery on ASD drug absorption and metabolism leading. Pre- and post-surgical serum concentrations should be measured in patients with seizures or epilepsy receiving ASDs.

Potential gut-brain mechanisms behind adverse mental health outcomes of bariatric surgery

Bariatric surgery induces sustained weight loss and metabolic benefits via notable effects on the gut-brain axis that lead to alterations in the neuroendocrine regulation of appetite and glycaemia. However, in a subset of patients, bariatric surgery is associated with adverse effects on mental health, including increased risk of suicide or self-harm as well as the emergence of depression and substance use disorders. The contributing factors behind these adverse effects are not well understood. Accumulating evidence indicates that there are important links between gut-derived hormones, microbial and bile acid profiles, and disorders of mood and substance use, which warrant further exploration in the context of changes in gut-brain signalling after bariatric surgery. Understanding the basis of these adverse effects is essential in order to optimize the health and well-being of people undergoing treatment for obesity.

Serum concentrations of antidepressants, antipsychotics, and antiepileptics over the bariatric surgery procedure

Purpose

As a substantial proportion of bariatric surgery patients use psychotropic/antiepileptic drugs, we investigated the impact of this procedure on serum concentrations.

Methods

In a naturalistic, longitudinal, prospective case series, we compared dose-adjusted trough concentrations of antidepressants, antipsychotics, or antiepileptics in consecutive patients before and after bariatric surgery. Adherence to treatment over 2 weeks preceding each sampling was considered.

Results

In all, 85 participants were included (86% female, median age 45 years, median body mass index 42 kg/m²). They were being treated with 18 different psychotropic/antiepileptic drugs (7 substances: 6–17 individuals, 11 substances: 1–4 individuals) and contributed 237 samples over a median of 379 days after surgery. For four out of seven substances with pre-/post-surgery samples available from six or more individuals, the dose-adjusted concentration was reduced (sertraline: 51%, mirtazapine: 41%, duloxetine: 35%, citalopram: 19%). For sertraline and mirtazapine, the low-calorie-diet before surgery entirely explained this reduction. A consistent finding, irrespective of drug, was the association between the mean ratio of the post-/pre-diet dose-adjusted concentration and the lipophilicity of the drug (logD; correlation coefficient: −0.69, P = 0.0005), the low-calorie diet often affecting serum concentration more than the surgery itself.

Conclusions

Serum concentrations of psychotropic/antiepileptic drugs vary after bariatric surgery and can be hard to predict in individual patients, suggesting that therapeutic drug monitoring is of value. Conversely, effects of the pre-surgery, low-calorie diet appear generalizable, with decreased concentrations of highly lipophilic drugs and increased concentrations of highly hydrophilic drugs. Interaction effects (surgery/dose/concentration) were not evident but cannot be excluded.

Oral drug dosing following bariatric surgery: General concepts and specific dosing advice

Bariatric or weight‐loss surgery is a popular option for weight reduction. Depending on the surgical procedure, gastric changes like decreased transit time and volume and increased pH, decreased absorption surface in the small intestine, decreased exposure to bile acids and enterohepatic circulation, and decreased gastrointestinal transit time may be expected. In the years after bariatric surgery, patients will also substantially lose weight. As a result of these changes, the absorption, distribution, metabolism and/or elimination of drugs may be altered. The purpose of this article is to report the general influence of bariatric surgery on oral drug absorption, and to provide guidance for dosing of commonly used drugs in this special population. Upon oral drug administration, the time to maximum concentration is often earlier and this concentration may be higher with less consistent effects on trough concentrations and exposure. Additionally, prescription of liquid formulations to bariatric patients is supported by some reports, even though the high sugar load of these suspensions may be of concern. Studies on extended‐release medications result in an unaltered exposure for a substantial number of drugs. Also, studies evaluating the influence of timing after surgery show dynamic absorption profiles. Although for this group specific advice can be proposed for many drugs, we conclude that there is insufficient evidence for general advice for oral drug therapy after bariatric surgery, implying that a risk assessment on a case‐by‐case basis is required for each drug.

Impact of Bariatric Surgery on Medication Efficacy: an Analysis of World Health Organization Pharmacovigilance Data

Bariatric surgery is the most effective treatment of severe obesity. However, this surgery can have an impact on the bioavailability and metabolism of oral drugs as it modifies absorption, intestinal, and hepatic metabolism, and efflux transporter activity. The clinical impact of such modifications often remains unknown. To investigate, we extracted and summarized all reports of changes in drug efficacy associated with bariatric surgery registered in the WHO pharmacovigilance database. We identified 165 drug reports affecting 128 patients. The majority involved gastric bypass surgery (77.3%). Most reports concerned drug ineffectiveness (74.7%). The most frequent modifications concerned psychotropic drugs with a reduction in efficacy. This study underlines the urgent need for more research to better characterize the impact of bariatric surgery on drug pharmacokinetics and clinical efficacy.

[Not Available]

Objectif

Reconnaître les changements pharmacocinétiques prévisibles et émettre des recommandations pratiques quant à la prise en charge pharmacologique des maladies après une chirurgie bariatrique.

Sources d’information

Une recherche a été effectuée dans MEDLINE, EMBASE, PubMed, Scopus et dans la bibliothèque Cochrane. La recherche se limitait aux études menées chez l’être humain. Les mots-clés de la recherche étaient : obesity, obese, bariatric surgery, gastric bypass, gastrectomy, gastric band, RYGB, roux-en-y, gastrointestinal absorption, medication absorption, drug absorption, bioavailability, dose adjust, drug monitoring, medication adjust, drug change, medication change, medication management et medication dosing. Une recherche à la main a également été réalisée dans les références des études et des articles de synthèse originaux. Les études incluses ont été entrées dans PubMed et les articles apparaissant sous l’en-tête « articles semblables » ont également été examinés. Seules les études portant sur les chirurgies bariatriques pratiquées au Canada (c.-à-d. dérivation gastrique de Roux-en-Y, gastrectomie longitudinale [en manchon] ou anneau gastrique) ont été incluses.

Message principal

Les changements pharmacocinétiques auxquels il faut s’attendre après la chirurgie bariatrique varient en fonction du type de chirurgie. Plusieurs principes directeurs de gestion des schémas pharmacologiques peuvent être appliqués après la chirurgie bariatrique. Des conseils pratiques sont aussi présentés pour gérer la médication dans le contexte de maladies précises.

Conclusion

Après la chirurgie bariatrique, il faut s’attendre à changer les schémas pharmacologiques à long terme, et ceux-ci doivent être bien gérés, de façon ponctuelle. Les recommandations de pratique clinique fournies peuvent être conjuguées au tableau clinique du patient afin d’ajuster correctement les schémas pharmacologiques à long terme après la chirurgie bariatrique en se fondant sur les données probantes.

Medication management and pharmacokinetic changes after bariatric surgery

OBJECTIVE

To identify expected pharmacokinetic changes and provide practical recommendations for the medication management of chronic disease states after bariatric surgery.

SOURCES OF INFORMATION

MEDLINE, EMBASE, PubMed, Scopus, and the Cochrane Library were searched. The search was limited to studies in human adults. Search terms included obesity, obese, bariatric surgery, gastric bypass, gastrectomy, gastric band, RYGB, roux-en-y, gastrointestinal absorption, medication absorption, drug absorption, bioavailability, dose adjust, drug monitoring, medication adjust, drug change, medication change, medication management, and medication dosing. Reference lists of original studies and reviews were also hand searched. Included studies were entered into PubMed and articles under the "Similar articles" heading were also reviewed. Only studies relevant to bariatric surgery types currently available in Canada (ie, Roux-en-Y gastric bypass, sleeve gastrectomy, or gastric banding) were included.

MAIN MESSAGE

Pharmacokinetic changes anticipated after bariatric surgery vary by surgery type. There are several guiding principles that might be applied to medication management regimens after bariatric surgery. Practice tips are also presented for medication management of specific chronic disease states.

CONCLUSION

Changes to long-term medication regimens after bariatric surgery should be anticipated and managed in an appropriate and timely manner. The provided clinical practice recommendations might be used in conjunction with a patient's clinical picture to adjust chronic medication regimens in an appropriate and evidence-based manner after bariatric surgery.

Pharmacokinetic changes post-bariatric surgery: A scoping review

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.

Psychiatric Management of Bariatric Surgery Patients: A Review of Psychopharmacological and Psychological Treatments and Their Impact on Postoperative Mental Health and Weight Outcomes

BACKGROUND

Bariatric surgery is an effective treatment for severe obesity; however, high rates of psychiatric comorbidity complicate bariatric surgery care. As a result, importance has been placed on the need for ongoing psychiatric support in patients undergoing bariatric surgery. Given the lack of conclusive presurgery psychosocial predictors of postoperative mental health outcomes, studies have now shifted their focus to understand the long-term psychosocial sequalae that arise after surgery. Increasing evidence has demonstrated the potential for psychiatric care to stabilize psychiatric symptoms and minimize patient distress.

OBJECTIVE

To review psychopharmacological and psychological interventions for patients undergoing bariatric surgery and their impact on mental health and weight outcomes after surgery.

METHODS

We performed a comprehensive literature search in Ovid MEDLINE for studies examining the impact of psychopharmacological and psychological treatments on bariatric patients' postoperative mental health and weight outcomes.

RESULTS

Overall, 37 studies were included in the review. Preliminary evidence suggests that psychiatric medications do not negatively impact weight loss or health-related quality of life in the short term; however, more rigorous research designs are needed. There are insufficient data on specific psychiatric medications and long-term impact on weight loss and psychosocial outcomes. Postoperative psychological interventions have evidence for improving eating psychopathology, anxiety, and depressive symptoms; however, effects on weight loss remain unclear.

CONCLUSION

Evidence for psychopharmacological and psychological treatments remains preliminary. Consideration should be given to integrated, stepped-care models to provide personalized psychiatric interventions after surgery. Future research on expanding current psychiatric interventions, timing of delivery, and predictors of response is needed.

The Impact of Proximal Roux-en-Y Gastric Bypass Surgery on Acetaminophen Absorption and Metabolism

BACKGROUND

Roux-en-Y gastric bypass (RYGBS), a surgery that creates a smaller stomach pouch and reduces the length of small intestine, is one of the most common medical interventions for the treatment of obesity.

AIM

The aim of this study was to determine how RYGBS affects the absorption and metabolism of acetaminophen.

MATERIALS AND METHODS

Ten morbidly obese patients received 1.5 g of liquid acetaminophen (APAP) orally on three separate pharmacokinetic study days (i.e., pre-RYGBS baseline and 3 and 12 months post-RYGBS). Plasma was collected at pre-specified timepoints over 24 hours, and the samples were analyzed using liquid chromatography-mass spectrometry for APAP, APAPglucuronide (APAP-gluc), APAP-sulfate (APAP-sulf), APAP-cysteine (APAP-cys), and APAP-Nacetylcysteine (APAP-nac).

RESULT

Following RYGBS, peak APAP concentrations at the 3-month and 12-month visits increased by 2.0-fold compared to baseline (p=0.0039 and p=0.0078, respectively) and the median time to peak concentration decreased from 35 to 10 minutes. In contrast, peak concentrations of APAP-gluc, APAP-sulf, APAP-cys, and APAP-nac were unchanged following RYGBS. The apparent oral clearance of APAP and the ratios of metabolite area under the curve (AUC)-to-APAP AUC for all four metabolites decreased at 3 and 12 months post-RYGBS compared to the presurgical baseline. In a simulation of expected steady-state plasma concentrations following multiple dosing of 650 mg APAP every 4 hours, post-RYGBS patients had higher steady-state peak APAP concentrations compared to healthy individuals and obese pre-RYGBS patients, though APAP exposure was unchanged compared to healthy individuals.

CONCLUSION

Following RYGBS, the rate and extent of APAP absorption increased and decreased formation of APAP metabolites was observed, possibly due to downregulation of Phase II and cytochrome P450 2E1 enzymes.

Modern pharmacological treatment of obese patients

There are many angles to consider in drug treatment of obese patients. On the one hand, some specific weight loss drugs are available, on the other, several drugs are associated with unintentional weight changes. When treating an obese patient for any given disease, several physiological changes may influence the pharmacokinetic properties of the drugs required. Thus, increased body weight may influence the efficacy and safety of some drug treatments. Even more complicated is the situation after weight reduction surgery. Due to the various changes to the gastrointestinal tract induced by the different surgical techniques used, and the dynamic changes in body composition thereafter, drug dosing has to be constantly reconsidered. Whereas all of these issues are of clinical importance, none of them have been investigated in the necessary depth and broadness to ensure safe and efficacious drug treatment of the massively obese patient. Individual considerations have to be based on comorbidities, concomitant medication, and on specific drug properties, for example, lipophilicity, volume of distribution, and metabolism. In this article we summarize the data available on different aspects of drug treatment in the obese patient with the hope of improving patient care.

The influence of bariatric surgery on oral drug bioavailability in patients with obesity: A systematic review

Anatomical changes in the gastrointestinal tract and subsequent weight loss may influence drug disposition and thus drug dosing following bariatric surgery. This review systematically examines the effects of bariatric surgery on drug pharmacokinetics, focusing especially on the mechanisms involved in restricting oral bioavailability. Studies with a longitudinal before-after design investigating the pharmacokinetics of at least one drug were reviewed. The need for dose adjustment following bariatric surgery was examined, as well as the potential for extrapolation to other drugs subjected to coinciding pharmacokinetic mechanisms. A total of 22 original articles and 32 different drugs were assessed. The majority of available data is based on Roux-en-Y gastric bypass (RYGBP) (18 of 22 studies), and hence, the overall interpretation is more or less limited to RYGBP. In the case of the majority of studied drugs, an increased absorption rate was observed early after RYGBP. The effect on systemic exposure allows for a low degree of extrapolation, including between drugs subjected to the same major metabolic and transporter pathways. On the basis of current understanding, predicting the pharmacokinetic change for a specific drug following RYGBP is challenging. Close monitoring of each individual drug is therefore recommended in the early postsurgical phase. Future studies should focus on the long-term effects of bariatric surgery on drug disposition, and they should also aim to disentangle the effects of the surgery itself and the subsequent weight loss.

Lurasidone Malabsorption Following Bariatric Surgery: A Case Report

A significant segment of the United States adult population is obese. Bariatric surgery is one approach to weight loss when nonsurgical efforts have failed. In individuals with a body mass index ≥50, gastric reduction with duodenal switch is more effective than gastric bypass. More than half of bariatric surgery candidates report a history of mental illness and more than one third were taking at least one psychotropic medication at the time of surgery. Thus, the impact of surgery on absorption of psychiatric medications should be considered. Lurasidone, a second-generation antipsychotic used to treat schizophrenia and bipolar disorder, is recommended to be taken with food of at least 350 calories. We describe the case of a patient with incomplete response to lurasidone therapy in the year following a duodenal switch procedure. This case raises concern about the effect that the duodenal switch procedure may have on lurasidone absorption.

Psychosocial Concerns Following Bariatric Surgery: Current Status

PURPOSE OF REVIEW

The purpose of this paper is to review the current status of research on psychosocial concerns following bariatric surgery.

RECENT FINDINGS

Bariatric surgery has a positive overall impact on weight and obesity-related comorbidities, as well as a positive short-term impact on mental health and psychosocial functioning. Nonetheless, research has documented a number of different psychosocial concerns that may emerge following surgery including maladaptive eating, substance use disorders, suicide, lack of social support, and excess skin. Moreover, special populations of patients may have distinctive psychosocial concerns based on sociodemographic factors such as age or severity of obesity. Available studies suggest that psychosocial interventions have a positive impact on post-surgery outcomes, particularly maladaptive eating. However, research is limited, and long-term data are lacking. Monitoring patients after bariatric surgery for negative psychosocial outcomes is warranted. Research is needed to develop and evaluate personalized approaches to optimize long-term weight loss and psychosocial adjustment.

Prevalence and Factors Associated With Psychiatric Medication Use in Bariatric Surgery Candidates

OBJECTIVE

We aimed to describe the rates of psychiatric medication use in bariatric surgery candidates and factors associated with psychiatric medication use.

METHODS

Patients from the Toronto Western Hospital Bariatric Surgery Program were recruited from 2011 to 2014. Data extracted included demographics, clinical factors (e.g., mood disorder, anxiety disorder, eating disorder, Patient Health Questionnaire-9, Generalized Anxiety Disorder 7), and psychiatric medication use. Logistic regression analyses were used to examine the relationship between demographic variables, clinical factors, and psychiatric medication use. Multiple logistic regression was conducted to determine the predictors of clinical factors from demographic variables with psychiatric medication use.

RESULTS

A total of 262 (35.1%) patients were taking at least 1 psychiatric medication and 105 patients (14.1%) were taking more than 1 psychiatric medication. Antidepressants were the most common psychiatric medication reported. The majority of patients taking a psychiatric medication had a psychiatric illness, with 16.0% not having a lifetime diagnosis of a mental illness. Being male and being employed significantly predicted lower odds of being on a psychiatric medication. Older age significantly predicted higher odds of being on a psychiatric medication. Psychiatric disorders were significantly associated with psychiatric medication use independent of demographic variables.

CONCLUSION

Our study provides insights into clinical and demographic factors related to psychiatric medication use in bariatric surgery patients. The findings support careful screening and clarification of psychiatric medications, especially in patients without a formal psychiatric diagnosis.

Impact of body weight, low energy diet and gastric bypass on drug bioavailability, cardiovascular risk factors and metabolic biomarkers: protocol for an open, non-randomised, three-armed single centre study (COCKTAIL)

INTRODUCTION

Roux-en-Y gastric bypass (GBP) is associated with changes in cardiometabolic risk factors and bioavailability of drugs, but whether these changes are induced by calorie restriction, the weight loss or surgery per se, remains uncertain. The COCKTAIL study was designed to disentangle the short-term (6 weeks) metabolic and pharmacokinetic effects of GBP and a very low energy diet (VLED) by inducing a similar weight loss in the two groups.

METHODS AND ANALYSIS

This open, non-randomised, three-armed, single-centre study is performed at a tertiary care centre in Norway. It aims to compare the short-term (6 weeks) and long-term (2 years) effects of GBP and VLED on, first, bioavailability and pharmacokinetics (24 hours) of probe drugs and biomarkers and, second, their effects on metabolism, cardiometabolic risk factors and biomarkers. The primary outcomes will be measured as changes in: (1) all six probe drugs by absolute bioavailability area under the curve (AUC_oral/AUC_iv) of midazolam (CYP3A4 probe), systemic exposure (AUC_oral) of digoxin and rosuvastatin and drug:metabolite ratios for omeprazole, losartan and caffeine, levels of endogenous CYP3A biomarkers and genotypic variation, changes in the expression and activity data of the drug-metabolising, drug transport and drug regulatory proteins in biopsies from various organs and (2) body composition, cardiometabolic risk factors and metabolic biomarkers.

ETHICS AND DISSEMINATION

The COCKTAIL protocol was reviewed and approved by the Regional Committee for Medical and Health Research Ethics (Ref: 2013/2379/REK sørøst A). The results will be disseminated to academic and health professional audiences and the public via presentations at conferences, publications in peer-reviewed journals and press releases and provided to all participants.

TRIAL REGISTRATION NUMBER

NCT02386917.

Surgical Management of Obesity Among People with Schizophrenia and Bipolar Disorder: a Systematic Review of Outcomes and Recommendations for Future Research

BACKGROUND

People with schizophrenia or bipolar disorder (BD) exhibit very high levels of obesity. Little is known about the potential benefits/risks of obesity surgery. We conducted a narrative review to summarize the available knowledge on bariatric surgery in people with schizophrenia or BD.

METHODS

A systematic search was conducted of major electronic databases from inception to October 2016 for studies investigating bariatric surgery among people with schizophrenia or BD. Data were presented in a narrative synthesis and future research strategies proposed.

RESULTS

The electronic database searches identified 44 records. Eight studies (BD, n = 265; schizophrenia: n = 14) were included with a mean study length of 15.7 months (12-24). Seven found that bariatric surgery resulted in weight loss in those with psychiatric disorders with an excess weight loss ranging -31 to -70%. Six studies found that weight loss from bariatric surgery was similar in people with schizophrenia or BD versus controls. However, most of the studies limited their outcomes to only weight loss and did not measure whether obesity surgery affected the status and treatment of psychiatric symptoms. Although few adverse events were reported among patients with BD, data from two studies demonstrated no significant deterioration of psychiatric symptoms post-surgery in people with schizophrenia.

CONCLUSIONS

Growing evidence suggests that bariatric surgery may improve short-term weight status among people with BD. However, given the paucity of studies for schizophrenia, and the lack of information on medium-to long-term results, future large-scale high-quality studies are required.

The Effect of Roux-en-Y Gastric Bypass Surgery in Morbidly Obese Patients on Pharmacokinetics of (Acetyl)Salicylic Acid and Omeprazole: the ERY-PAO Study

BACKGROUND

Data on the absorption of orally administered drugs following Roux-en-Y gastric bypass (RYGB) surgery in obese patients are limited and inconclusive. As it is difficult to predict changes in absorption, studies on frequently used drugs in this population are necessary. Acetylsalicylic acid (ASA) and omeprazole are two commonly prescribed drugs in obese patients.

METHODS

In this repeated measures study, omeprazole and salicylic acid (SA) serum concentrations were measured before and after RYGB in 34 morbidly obese subjects. Time to maximum concentration (Tmax), lag time (Tlag), maximum concentration (Cmax), and area under the serum concentration versus time curve (AUC) were calculated for both drugs to determine possible differences in drug absorption after the procedure.

RESULTS

For SA, Tmax significantly decreased after RYGB, while both Cmax and AUC0-24 significantly increased. For omeprazole, both Tmax and Tlag significantly decreased after RYGB, while Cmax significantly increased. Mean AUC0-12 significantly decreased post-surgery. The difference in AUC0-12 before and after surgery varied between subjects.

CONCLUSIONS

Our study shows a faster absorption of both ASA and omeprazole after RYGB. The exposure to ASA is higher post-surgery, but the standard dose of 80 mg does not need to be modified, considering its range in effective dose. The exposure to omeprazole is, on average, decreased after surgery. Clinicians should be aware to increase the dose of omeprazole if symptoms suggest inadequate response.

RYGB and Drug Disposition: How to Do Better? Analysis of Pharmacokinetic Studies and Recommendations for Clinical Practice

An important issue in the follow-up of patients with bariatric surgery remains to determine whether their therapeutic management should be different after surgery. In this article, we first reviewed all pharmacokinetic studies involving at least four subjects who underwent the Roux-en-Y gastric bypass (RYGB) bariatric surgery. Twenty-five publications were selected and, overall, 25 drugs were studied. Drug solubility and permeability parameters for each drug were defined using different parameters or classifications. Increased rates of oral drug absorption were predominantly observed. Conversely, drug exposure differed from one drug to another. Considering the galenic formulation and the Biopharmaceutics Classification System (BCS) class may help the prediction of oral drug exposure outcome after RYGB. We propose a strategy aiming to guide prescription and drug monitoring in patients with RYGB. But further research is clearly needed due to the unique characteristics of the bariatric population. Priority should be given to drugs that do not have clinical or biological surrogates for dose adaptation.

Comparison of Bioavailability of Single-Dose Extended-Release Venlafaxine Capsules in Obese Patients Before and After Gastric Bypass Surgery

STUDY OBJECTIVE

The extended-release (ER) form of venlafaxine is preferred because of improved patient adherence, but the immediate-release (IR) form is frequently used after Roux-en-Y gastric bypass (RYGB) surgery because of concerns for malabsorption. The objective of this study was to determine whether a statistically significant and predictable change in the bioavailability of venlafaxine ER capsules occurs after RYGB.

DESIGN

Prospective nonblinded single-dose pharmacokinetic study.

SETTING

Clinical research unit at a large tertiary care medical practice.

PATIENTS

Ten adult pre-bariatric surgery patients who met the criteria for noncomplicated RYGB were enrolled and served as their own controls.

INTERVENTIONS

Patients were administered one venlafaxine ER 75-mg capsule at two visits-the first visit at least 1 week before undergoing RYGB and the second visit 3-4 months after RYGB. Blood samples were collected at predetermined intervals over 48 hours after each dose, and the pharmacokinetics of venlafaxine were measured.

MEASUREMENTS AND MAIN RESULTS

Plasma levels of venlafaxine and its primary metabolite, O-desmethylvenlafaxine (ODV), were compared at baseline and 3-4 months after RYGB. The areas under the serum concentration-time curves from 0-24 hours (AUC_0-24 ) for venlafaxine (mean ± SD 734 ± 602 vs 630 ± 553 ng·hr/ml, p=0.22) and ODV (mean ± SD 894 ± 899 vs 1083 ± 972 ng·hr/ml, p=0.07) were similar before and after RYGB. Using a bioequivalence approach, differences in pre-RYGB and post-RYGB values of AUC_0-24 , peak serum concentration, and time to peak serum concentration were not statistically significant for either venlafaxine or ODV.

CONCLUSION

This study suggests that RYGB does not significantly alter the amount of venlafaxine or its active metabolite, ODV, absorbed from a venlafaxine ER capsule or the time over which it is absorbed.

Weight and Metabolic Outcomes 12 Years after Gastric Bypass

BACKGROUND

Few long-term or controlled studies of bariatric surgery have been conducted to date. We report the 12-year follow-up results of an observational, prospective study of Roux-en-Y gastric bypass that was conducted in the United States.

METHODS

A total of 1156 patients with severe obesity comprised three groups: 418 patients who sought and underwent Roux-en-Y gastric bypass (surgery group), 417 patients who sought but did not undergo surgery (primarily for insurance reasons) (nonsurgery group 1), and 321 patients who did not seek surgery (nonsurgery group 2). We performed clinical examinations at baseline and at 2 years, 6 years, and 12 years to ascertain the presence of type 2 diabetes, hypertension, and dyslipidemia.

RESULTS

The follow-up rate exceeded 90% at 12 years. The adjusted mean change from baseline in body weight in the surgery group was -45.0 kg (95% confidence interval [CI], -47.2 to -42.9; mean percent change, -35.0) at 2 years, -36.3 kg (95% CI, -39.0 to -33.5; mean percent change, -28.0) at 6 years, and -35.0 kg (95% CI, -38.4 to -31.7; mean percent change, -26.9) at 12 years; the mean change at 12 years in nonsurgery group 1 was -2.9 kg (95% CI, -6.9 to 1.0; mean percent change, -2.0), and the mean change at 12 years in nonsurgery group 2 was 0 kg (95% CI, -3.5 to 3.5; mean percent change, -0.9). Among the patients in the surgery group who had type 2 diabetes at baseline, type 2 diabetes remitted in 66 of 88 patients (75%) at 2 years, in 54 of 87 patients (62%) at 6 years, and in 43 of 84 patients (51%) at 12 years. The odds ratio for the incidence of type 2 diabetes at 12 years was 0.08 (95% CI, 0.03 to 0.24) for the surgery group versus nonsurgery group 1 and 0.09 (95% CI, 0.03 to 0.29) for the surgery group versus nonsurgery group 2 (P<0.001 for both comparisons). The surgery group had higher remission rates and lower incidence rates of hypertension and dyslipidemia than did nonsurgery group 1 (P<0.05 for all comparisons).

CONCLUSIONS

This study showed long-term durability of weight loss and effective remission and prevention of type 2 diabetes, hypertension, and dyslipidemia after Roux-en-Y gastric bypass. (Funded by the National Institute of Diabetes and Digestive and Kidney Diseases and others.).

Oral drug therapy following bariatric surgery: an overview of fundamentals, literature and clinical recommendations

Bariatric surgery is the most effective solution for severe obesity and obesity with comorbidities, and the number of patients going through bariatric surgery is rapidly and constantly growing. The modified gastrointestinal anatomy of the patient may lead to significant pharmacokinetic alterations in the oral absorption of drugs after the surgery; however, because of insufficient available literature and inadequate awareness of the medical team, bariatric surgery patients may be discharged from the hospital with insufficient instructions regarding their medication therapy. In this article, we aim to present the various mechanisms by which bariatric surgery may influence oral drug absorption, to provide an overview of the currently available literature on the subject, and to draw guidelines for the recommendations bariatric surgery patients should be instructed before leaving the hospital. To date, and until more robust data are published, it is essential to follow and monitor patients closely for safety and efficacy of their medication therapies, both in the immediate and distant time post-surgery.

Decreased Escitalopram Concentrations Post-Roux-en-Y Gastric Bypass Surgery

BACKGROUND

There is a high coincidence between obesity and psychiatric disorders including depression. Depressive disorders are commonly treated with antidepressants, including the selective serotonin reuptake inhibitor Lexapro (escitalopram). Although candidates for elective Roux-en-Y gastric bypass (RYGB) surgery may be treated with escitalopram, drug dosing strategies are typically not adjusted postoperatively. Therefore, studies are needed to better characterize escitalopram drug concentrations in a postsurgical setting.

METHODS

Turbulent flow-liquid chromatographic-tandem mass spectrometric methods were used to quantify escitalopram concentrations in serum in study participants approved for RYGB. Blood was collected from study subjects 2 weeks before surgery, and 2 and 6 weeks postoperatively, to assess the impact of RYGB on systemic drug concentrations.

RESULTS

Twelve samples from 4 study participants were collected and analyzed for serum escitalopram concentrations. Two weeks post-RYGB, although there were minimal changes in each participant's body mass index (<5%), drug concentrations were 33% (4%-71%) decreased as compared with presurgical serum concentrations. There were further decreases in drug concentrations 6 weeks postsurgery. All clinical laboratory values were within normal reference intervals.

CONCLUSIONS

RYGB significantly alters the gastrointestinal tract and impacts escitalopram drug concentrations, even shortly after surgery.

Sleeve gastrectomy surgery in obese patients post-organ transplantation

BACKGROUND

Among organ transplant recipients, a common side effect of immunosuppressive therapy is the development of obesity, which affects a third of the patients within 3 years after transplantation. Bariatric surgery represents a possible surgical option for weight loss among posttransplant patients.

OBJECTIVES

The aim of this study was to examine percent excess weight loss (%EWL), and percent weight loss (%WL) and perioperative and postoperative complications in posttransplant obese patients after sleeve gastrectomy (SG) compared with nontransplant patients. We hypothesize that transplant patients who undergo SG will not significantly differ in their perioperative or postoperative complications or in their %EWL and %WL compared with nontransplant patients who undergo SG. The second aim was to evaluate the impact of SG on graft function and immunosuppressive therapy in transplant patients.

SETTING

University hospital.

METHODS

Among 500 consecutive patients who underwent SG from January 2008 to June 2014, 10 patients were organ transplant recipients. The following variables were compared between groups: patient demographic characteristics and co-morbidities, type of transplant surgery, date of transplant surgery, pretransplant body mass index (BMI), date of bariatric surgery, prebariatric surgery BMI, operative time, length of hospitalization, postoperative complications, and change in BMI, %EWL, and %WL. Data were also collected on renal, liver, and pancreas graft function parameters and changes in immunosuppressive medications.

RESULTS

Six patients had a kidney transplant, 2 patients had a liver transplant, and 2 had a pancreas transplant. No significant differences were observed in %EWL or %WL at 6 and 12 months follow-up between transplant and nontransplant patients. No transplant patients were lost to follow-up at 6 and 12 months. Among nontransplant patients, 36.7% and 35.7% were lost to follow-up at 6 and 12 months, respectively. No postoperative complications were registered in the transplant group. SG did not negatively affect the graft function.

CONCLUSION

Initials results found that there were no significant differences in %EWL or %WL at 6 and 12 months follow-up between transplant and nontransplant patients. There were also no perioperative and postoperative complications among transplant patients after SG.