Long-term Effect of Bariatric Surgery on the Use of Levothyroxine and Thyroid Levels

BACKGROUND: The aim of this study was to evaluate the effect of bariatric surgery on the defined daily dose of levothyroxine (DDD LT4), thyroid-stimulating hormone (TSH), and free thyroxine (fT4) in female patients with hypothyroidism until 48 months after surgery. METHODS: A retrospective observational study of hypothyroid patients who underwent bariatric surgery. Changes in DDD LT4, TSH, and fT4 over a 48 month period after surgery were analyzed. RESULTS: Thirty-seven patients were included: 27 Roux-en-Y gastric bypass (RYGB), 6 sleeve gastrectomy (SG), 3 adjustable gastric band, and 1 one anastomosis gastric bypass. The median DDD LT4 decreased from 125 µg at baseline to 100 µg 12 months after surgery. From 24 to 48 months after surgery, the median DDD LT4 was stable at 125 µg. Most dose adjustments occurred during the first 24 months after surgery. In the time period of 24-48 months after surgery, the dose remained stable in 73.1% of the RYGB patients and in 60.0% of the SG patients. After 48 months in the RYGB group, no significant change in TSH and fT4 levels was observed. CONCLUSIONS: Bariatric surgery led to frequent dose adjustments during the first 2 years after surgery. However, 24-48 months after surgery in the majority of patients, the dosage remained stable. No significant change in TSH and fT4 was observed 48 months after RYGB. In the first 2 years after surgery, clinicians should frequently monitor TSH and fT4 for individual dose adjustment of levothyroxine. Thereafter, the frequency of monitoring may be decreased

Prescribing Challenges after Bariatric Surgery

Obesity is an increasing problem in the UK, with over half the population being overweight or obese. The use of gastric surgery is increasing, with a 5% increase in 2016/17 compared to 2015/16. However, little is known about ideal drug formulations after bariatric surgery. An exploratory literature search of research databases was carried out to address this. We found that there was a dearth of high-quality primary studies available, with many studies using low numbers of participants. The major finding was of the need for increased vigilance and monitoring of patients after surgery

A rapid and simple determination of A77 1726 in human serum by high-performance liquid chromatography and its application for optimization of leflunomide therapy

Leflunomide is a disease-modifying antirheumatic drug, which is bioactivated by fort-nation of A77 1726. In this study a rapid and simple quantitative assay using a reversed phase HPLC-UV method is validated for detection of A77 1726 in human serum. The HPLC-UV method uses a mobile phase consisting of methanol and a KH2PO4-buffer (45 mM, pH = 3) (50:50,v/v), at a flow rate of I mL/min. A77 1726 is detected by UV-absorption at 295 nm with a retention time of 8.9 min. Demoxepam is used as internal standard. Validation showed lower and upper limits of quantitation of 0.5 and 100 mg/L, respectively. The assay was linear over the concentration range of 0.5-100 mg/L (r(2) > 0.999). Intra- and inter-day precision showed coefficients of variation within 15% over the complete concentration range; accuracy was within 8%. Commonly prescribed drugs to treat rheumatoid arthritis like disease-modifying antirheumatic drugs, analgesics and corticosteroids, and their main metabolites, are separated from A77 1726 with a resolution >2. Serum levels of A77 1726 in 37 patients on leflunomide therapy were determined using this HPLC-UV method. Measured serum A77 1726 serum concentrations in patient samples showed large variability with a range of 3-176 mg/L. (C) 2004 Elsevier B.V. All rights reserved

Therapeutic drug monitoring of A77 1726, the active metabolite of leflunomide. Serum concentrations predict response to therapy in patients with rheumatoid arthritis

Background: Leflunomide is the prodrug of the disease modifying antirheumatic metabolite A77 1726. More than 50% of patients withdraw from leflunomide treatment within one year, mainly because of adverse drug reactions. Therapeutic drug monitoring of A77 1726 may be useful in predicting the efficacy of leflunomide treatment. Objective: To study the relation between A77 1726 steady state serum concentrations and disease activity using the 28 joint (DAS28) response. Methods: Outpatients with rheumatoid arthritis on a stable leflunomide dose for >4 months were included. DAS28 score and adverse drug reactions were recorded. Blood samples were taken for determination of A77 1726 concentrations. The primary end point was the relation of serum A77 1726 concentrations with DAS28 response category Results: Serum A77 1726 concentrations were determined in 52 patients. A receiver operating characteristic (ROC) curve showed an area under the curve (AUC) of 0.73 (95% confidence interval, 0.54 to 0.93) (p<0.05). The sensitivity exceeded 99% at concentrations below 16 mg/l. DAS28 values at the point of sampling showed no relation with A77 1726 concentrations (AUC of the ROC curve = 0.50 (0.33 to 0.67) (NS)). Conclusions: A77 1726 steady state serum concentrations show a relation with DAS28 response. Determination of serum A77 1726 concentrations in patients with insufficient response to treatment may help when decisions have to be made about continuation of treatment or dose adjustment

A rapid and simple determination of A77 1726 in human serum by high-performance liquid chromatography and its application for optimization of leflunomide therapy

Leflunomide is a disease-modifying antirheumatic drug, which is bioactivated by fort-nation of A77 1726. In this study a rapid and simple quantitative assay using a reversed phase HPLC-UV method is validated for detection of A77 1726 in human serum. The HPLC-UV method uses a mobile phase consisting of methanol and a KH2PO4-buffer (45 mM, pH = 3) (50:50,v/v), at a flow rate of I mL/min. A77 1726 is detected by UV-absorption at 295 nm with a retention time of 8.9 min. Demoxepam is used as internal standard. Validation showed lower and upper limits of quantitation of 0.5 and 100 mg/L, respectively. The assay was linear over the concentration range of 0.5-100 mg/L (r(2) > 0.999). Intra- and inter-day precision showed coefficients of variation within 15% over the complete concentration range; accuracy was within 8%. Commonly prescribed drugs to treat rheumatoid arthritis like disease-modifying antirheumatic drugs, analgesics and corticosteroids, and their main metabolites, are separated from A77 1726 with a resolution >2. Serum levels of A77 1726 in 37 patients on leflunomide therapy were determined using this HPLC-UV method. Measured serum A77 1726 serum concentrations in patient samples showed large variability with a range of 3-176 mg/L. (C) 2004 Elsevier B.V. All rights reserved

A GASTROINTESTINAL SIMULATION SYSTEM (GISS) FOR DISSOLUTION OF DRUGS BEFORE AND AFTER ROUX-EN-Y GASTRIC BYPASS:FIRST RESULTS

Introduction Roux-en-Y gastric bypass (RYGB) surgery is the most commonly performed procedure in bariatric surgery, greatly reducing stomach size and bypassing much of the small intestine. Hence it may reduce the absorption and bioavai-lability of oral medications, especially modified release products. However, the pharmacokinetics of drugs after RYGB are poorly studied. An in vitro dissolution method simulating the conditions before and after RYGB might be a valuable tool to predict the behaviour of drugs with possible bioavailability problems in vivo. The objective of this study was to develop a gastrointestinal simulation system (GISS) mimicking conditions before and after RYGB for investigating dissolution characteristics of oral medications. Methods The GISS is a dissolution method which is based on a design by Schellekens et al. [1]. The GISS enables variation in parameters which are relevant to drug release in vivo: pH, volume, transit time, osmolality and agitation. During the test an oral drug formulation is exposed to solutions simulating stomach, (duodenum) jejunum, ileum and colon in fasting and non-fasting conditions before and after RYGB. Metoprolol immediate (IR) and controlled release (CR) tablets were tested in triplo. Release profiles were determined by measuring the concentrations of metoprolol spectrophotometrically. Results The GISS is able to expose an oral dosage form to subsequent environments simulating fasting and non-fasting conditions before and after RYGB. So far, release profiles of the tested products have been studied in conditions before RYGB. In non-fasting conditions after 30 min the release of metoprolol from the IR tablet is complete. From the CR tablet after 300 min almost 30 % of metoprolol is released. Conclusion A GISS has been developed to study release behaviour of medication during its passage through the gastrointestinal tract in fasting and non-fasting conditions before and after RYGB. Studies in which the situation after RYGB is simulated are in progress

Diagnostic Yield of Next Generation Sequencing in Genetically Undiagnosed Patients with Primary Immunodeficiencies : a Systematic Review

BACKGROUND: As the application of next generation sequencing (NGS) is moving to earlier stages in the diagnostic pipeline for primary immunodeficiencies (PIDs), re-evaluation of its effectiveness is required. The aim of this study is to systematically review the diagnostic yield of NGS in PIDs. METHODS: PubMed and Embase databases were searched for relevant studies. Studies were eligible when describing the use of NGS in patients that had previously been diagnosed with PID on clinical and/or laboratory findings. Relevant data on study characteristics, technological performance and diagnostic yield were extracted. RESULTS: Fourteen studies were eligible for data extraction. Six studies described patient populations from specific PID subcategories. The remaining studies included patients with unsorted PIDs. The studies were based on populations from Italy, Iran, Turkey, Thailand, the Netherlands, Norway, Saudi Arabia, Sweden, the UK, and the USA. Eight studies used an array-based targeted gene panel, four used WES in combination with a PID filter, and two used both techniques. The mean reported reading depth ranged from 98 to 1337 times. Five studies described the sensitivity of the applied techniques, ranging from 83 to 100%, whereas specificity ranged from 45 to 99.9%. The percentage of patients who were genetically diagnosed ranged from 15 to 79%. Several studies described clinical implications of the genetic findings. DISCUSSION: NGS has the ability to contribute significantly to the identification of molecular mechanisms in PID patients. The diagnostic yield highly depends on population and on the technical circumstances under which NGS is employed. Further research is needed to determine the exact diagnostic yield and clinical implications of NGS in patients with PID