Preliminary comparison of sertraline levels in postbariatric surgery patients versus matched nonsurgical cohort

Course of depressive symptoms and treatment in the longitudinal assessment of bariatric surgery (LABS-2) study

OBJECTIVE

To examine changes in depressive symptoms and treatment in the first 3 years following bariatric surgery.

METHODS

The longitudinal assessment of bariatric surgery-2 (LABS-2) is an observational cohort study of adults (n = 2,458) who underwent a bariatric surgical procedure at 1 of 10 US hospitals between 2006 and 2009. This study includes 2,148 participants who completed the Beck depression inventory (BDI) at baseline and ≥ one follow-up visit in years 1-3.

RESULTS

At baseline, 40.4% self-reported treatment for depression. At least mild depressive symptoms (BDI score ≥ 10) were reported by 28.3%; moderate (BDI score 19-29) and severe (BDI score ≥30) symptoms were uncommon (4.2 and 0.5%, respectively). Mild-to-severe depressive symptoms independently increased the odds (OR = 1.75; P = 0.03) of a major adverse event within 30 days of surgery. Compared with baseline, symptom severity was significantly lower at all follow-up time points (e.g., mild-to-severe symptomatology was 8.9%, 6 months; 8.4%, 1year; 12.2%, 2 years; 15.6%, 3 years; ps < 0.001), but increased between 1 and 3 years postoperatively (P < 0.01). Change in depressive symptoms was significantly related to change in body mass index (r = 0.42; P < 0001).

CONCLUSION

Bariatric surgery has a positive impact on depressive features. However, data suggest some deterioration in improvement after the first postoperative year. LABS-2, #NCT00465829, http://www.clinicaltrials.gov/ct2/show/NCT00465829.

Neuropsychological factors and bariatric surgery: a review

Obesity has become a global epidemic with associated physical, psychological, and cognitive deficits that tax the healthcare system and result in a significant economic burden. These costs have necessitated treatment measures to reduce the incidence of obesity as well as comorbidities associated with obesity. We review the current literature in order to describe the pre-surgical psychological and cognitive characteristics of individuals undergoing bariatric surgery and the possible changes in these functions following surgery. We discuss the importance of a pre-surgical evaluation that adequately evaluates cognitive and emotional functioning and what this evaluation should entail. Finally, we discuss recent trends in the types of bariatric surgeries being performed and how these changes may influence subsequent physical, cognitive, and emotional health.

The use of drugs in patients who have undergone bariatric surgery

According to the World Health Organization, obesity has become an epidemic in the 21st century affecting around 300 million people of all ages worldwide. Clinical treatment modalities for this disease are limited and ineffective when it comes to morbidly obese patients (body mass index – the weight in kilograms divided by height in meters squared – surpasses 40 kg/m²). Therefore, the alternative, surgical treatment, is the best option for these patients, namely gastric restrictive procedures or an intestinal bypass culminating in a malabsorptive syndrome. In the past 20 years, there has been a 70% increase in the number of bariatric procedures all over the world. The main pharmacokinetic consequence observed in the postoperative period of these individuals is a higher or lower absorption of orally administered drugs.

Psychiatric aspects of bariatric surgery

While most conventional treatments for individuals with severe obesity have a modest and short lived impact bariatric surgery has been consistently shown to result in long-term marked weight loss and significant improvement in medical comorbidities. Empirical data suggest a high prevalence of mental disorders among bariatric surgery candidates. This article reviews specific areas of psychopathology, problems in using psychopharmacological medications post-surgery, body contouring, and recommendations for pre and post-surgery care. Available research indicates a decrease in psychiatric symptoms post-surgery. However, in some patients the improvement appears to erode over time. Therefore, bariatric surgery patients should be monitored not only before surgery but also following surgery and referred for mental health treatment if problems develop.

A comparison of duloxetine plasma levels in postbariatric surgery patients versus matched nonsurgical control subjects

BACKGROUND

Bariatric surgery such as the Roux-en-Y gastric bypass (RYGB) is currently used as a treatment for severe obesity. Alteration of the gastrointestinal tract by this procedure suggests a potential for clinically significant alterations in the bioavailability of ingested medications including antidepressants.

OBJECTIVES

The purpose of this trial was to determine to what extent the RYGB procedure alters the area under the plasma concentration/time curve (AUC(0-infinity)) of the antidepressant, duloxetine.

METHODS

Ten subjects who were 1 year post-RYGB where compared with healthy control subjects matched for body mass index, age, and sex. Ultrarapid or poor metabolizers for cytochrome P450 2D6 were excluded from the study. Subjects received a single dose of 60 mg of duloxetine. Nineteen plasma samples were obtained during 72 hours to characterize the plasma level profile.

RESULTS

The mean AUC(0-infinity) was significantly smaller for the postbariatric surgery (PBS) group (646.74 ng × h/mL [SD, 79.70; range, 539.57-791.62], P = 0.017) compared to the nonsurgical control group (1119.91 ng × h/mL [SD, 593.40; range, 415.5-2426.56]). The Tmax was also significantly shorter for the PBS group (2.2 hours) compared to the nonsurgical control group (6 hours; P = 0.005). No significant difference in Cmax or half-life was identified.

CONCLUSIONS

To our knowledge, this is the first reported study exploring duloxetine pharmacokinetics PBS. This trial found that the bariatric surgery group was exposed to only 57.7% of duloxetine as compared to the nonsurgery group. This finding suggests that clinicians need to monitor patients closely after bariatric surgery and that further exploration of the effects of bariatric surgery on antidepressant pharmacokinetic parameters is warranted.

Possible risk factors for increased suicide following bariatric surgery

OBJECTIVE

There is a growing research literature suggesting that there may be elevated risk of suicide following bariatric surgery. Most of the data reported thus far has been cross-sectional and observational, and very little is known about the possible specific causal variables involved.

DESIGN AND METHODS

The purpose of this report is to review this literature and to review possible risk factors for increased suicidal risk following bariatric surgery, to delineate future research directions.

RESULTS

First a variety of medical, biological, and genetic factors, including the persistence or recurrence of medical comorbidities after bariatric surgery, the disinhibition and impulsivity secondary to changes in the absorption of alcohol, hypoglycemia, as well as pharmacokinetic changes that may affect the absorption of various medications including antidepressant medications are reviewed. Also reviewed are possible mediating factors involving changes in various peptidergic systems such as GLP-1 and Ghrelin. A number of psychosocial issues that might be involved are discussed, including lack of improvement in quality of life after surgery, continued or recurrent physical mobility restrictions, persistence or recurrence of sexual dysfunction and relationship problems, low self-esteem, and a history of child maltreatment. Inadequate weight loss or weight regain are also discussed.

CONCLUSIONS

A number of possible contributing factors have been identified. Possible theoretical models involved and directions for research are suggested.

Trends in oral drug bioavailability following bariatric surgery: examining the variable extent of impact on exposure of different drug classes

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

Changes to oral drug bioavailability have been observed post bariatric surgery. However, the magnitude and the direction of changes have not been assessed systematically to provide insights into the parameters governing the observed trends. Understanding these can help with dose adjustments.

WHAT THIS STUDY ADDS

Analysis of drug characteristics based on a biopharmaceutical classification system is not adequate to explain observed trends in altered oral drug bioavailability following bariatric surgery, although the findings suggest solubility to play an important role.

AIMS

To identify the most commonly prescribed drugs in a bariatric surgery population and to assess existing evidence regarding trends in oral drug bioavailability post bariatric surgery.

METHODS

A retrospective audit was undertaken to document commonly prescribed drugs amongst patients undergoing bariatric surgery in an NHS hospital in the UK and to assess practice for drug administration following bariatric surgery. The available literature was examined for trends relating to drug permeability and solubility with regards to the Biopharmaceutics Classification System (BCS) and main route of elimination.

RESULTS

No significant difference in the 'post/pre surgery oral drug exposure ratio' (ppR) was apparent between BCS class I to IV drugs, with regards to dose number (Do) or main route of elimination. Drugs classified as 'solubility limited' displayed an overall reduction as compared with 'freely soluble' compounds, as well as an unaltered and increased ppR.

CONCLUSION

Clinical studies establishing guidelines for commonly prescribed drugs, and the monitoring of drugs exhibiting a narrow therapeutic window or without a readily assessed clinical endpoint, are warranted. Using mechanistically based pharmacokinetic modelling for simulating the multivariate nature of changes in drug exposure may serve as a useful tool in the further understanding of postoperative trends in oral drug exposure and in developing practical clinical guidance.

Forensic Considerations in Bariatric Surgery Patients

Bariatric surgery is gaining in popularity in the United States and around the world as a treatment for morbid obesity. Patients seek surgery in order to lose weight and limit the long-term effects of insulin-resistant diabetes, heart disease and lung disease, including risk of sudden death. While gastric bypass in patients with morbid obesity can reduce the risk of diabetes and myocardial infarction to population levels, the risk of death remains increased. These patients may die suddenly and unexpectedly as a direct result of surgery, as an indirect result of surgery, or of end-organ damage wrought by years of obesity, completely unrelated to the surgery. Proper forensic pathologic assessment of these patients requires an understanding of the anatomic changes caused by bariatric surgery, the complications and the metabolic consequences of the different procedures. In order to better understand this subgroup of patients, a search of the peer-reviewed medical literature at the National Library of Medicine was conducted for articles using the keywords bariatric, surgery, gastric bypass, autopsy, review, toxicology, alcohol, drug, ethanol, absorption, elimination, litigation, forensic, and death. This review outlines the most common laparoscopic and open surgical procedures; the common immediate post-surgical complications that lead to morbidity and mortality; forensic toxicological considerations in bariatric patients; and the long-term complications and other causes that could lead to unexpected death in these patients.

Long-term effects of gastric bypass and duodenal switch on systemic exposure of atorvastatin

Background

A previous study of 22 patients undergoing either gastric bypass or duodenal switch showed increased systemic exposure of atorvastatin acid 3–8 weeks after surgery in the majority of patients. This study aimed to investigate the long-term effects on systemic exposure of atorvastatin acid in the same group of patients.

Methods

An 8-h pharmacokinetic investigation was performed a median of 27 months (range 21–45 months) after surgery. Systemic exposure was measured as the area under the plasma concentration versus the time curve from 0 to 8 h postdose (AUC_0–8). Linear mixed models with AUC_0–8 as the dependent variable were implemented to assess the effect of time, surgical procedure, and body mass index (BMI) as explanatory variables.

Results

The study enrolled 20 patients. The systemic exposure of atorvastatin acid changed significantly over time (p = 0.001), albeit there was substantial variation between subjects. The effect of time was attenuated but remained significant after adjustment for surgical procedure and BMI (p = 0.048). The initial AUC_0–8 increase seen in the majority of patients 3–8 weeks after surgery was normalized long term, with 7 of the 12 gastric bypass patients and 6 of the 8 duodenal switch patients showing decreased AUC_0–8 compared with preoperative values.

Conclusions

The systemic exposure of atorvastatin showed a significant change over time after bariatric surgery, albeit with large inter- and intraindividual variations. The findings indicate that patients using atorvastatin or drugs with similar pharmacokinetic properties should be monitored closely for both therapeutic effects and adverse events the first years after gastric bypass and duodenal switch. ClinicalTrial NCT00331565.

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

OBJECTIVE

Morbidly obese patients frequently present with mood and anxiety disorders, which are often treated with serotonin reuptake inhibitors (SRIs). Having observed that patients treated with SRIs frequently relapse after Roux-en-Y gastric bypass surgery, the authors sought to assess whether SRI bioavailability is reduced postoperatively.

METHOD

Twelve gastric bypass candidates treated with an SRI for primary mood or anxiety disorders were studied prospectively. Timed blood samples for SRI plasma levels were drawn for pharmacokinetic studies before surgery and 1, 6, and 12 months afterward. Maximum concentration, time to maximum concentration, and area under the concentration/time curve (AUC) were determined.

RESULTS

In eight of the 12 patients, AUC values 1 month after surgery dropped to an average of 54% (SD=18) of preoperative levels (range=36%-80%); in six of these patients, AUC values returned to baseline levels (or greater) by 6 months. Four patients had an exacerbation of depressive symptoms, which resolved by 12 months in three of them. Three of the four patients had a reduced AUC level at 1 month and either gained weight or failed to lose weight between 6 and 12 months. Normalization of the AUC was associated with improvement in symptom scores.

CONCLUSIONS

Patients taking SRIs in this study were at risk for reduced drug bioavailability 1 month after Roux-en-Y gastric bypass. The authors recommend close psychiatric monitoring after surgery.