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Thiopurine metabolites

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https://www.readbyqxmd.com/read/29324279/inhibition-of-udp-glucose-dehydrogenase-by-6-thiopurine-and-its-oxidative-metabolites-possible-mechanism-for-its-interaction-within-the-bilirubin-excretion-pathway-and-6tp-associated-liver-toxicity
#1
Chamitha J Weeramange, Cassie M Binns, Chixiang Chen, Ryan J Rafferty
6-Thiopurine (6TP) is an actively prescribed drug in the treatment of various diseases ranging from Crohn's disease and other inflammatory diseases to acute lymphocytic leukemia and non-Hodgkin's leukemia. While 6TP has beneficial therapeutic uses, severe toxicities are also reported with its use, such as jaundice and liver toxicity. While numerous investigations into the mode in which toxicity originates has been undertaken. None have investigated the effects of inhibition towards UDP-Glucose Dehydrogenase (UDPGDH), an oxidative enzyme responsible for UDP-glucuronic acid (UDPGA) formation or UDP-Glucuronosyl transferase (UGT1A1), which is responsible for the conjugation of bilirubin with UDPGA for excretion...
December 30, 2017: Journal of Pharmaceutical and Biomedical Analysis
https://www.readbyqxmd.com/read/29210335/predictive-role-of-nudt15-variants-on-thiopurine-induced-myelotoxicity-in-asian-inflammatory-bowel-disease-patients
#2
Natalia Sutiman, Sylvia Chen, Khoon Lin Ling, Sai Wei Chuah, Wai Fook Leong, Vinayak Nadiger, Madeline Tjai, Chris San Choon Kong, Brian John Schwender, Webber Chan, Hang Hock Shim, Wee Chian Lim, Chiea Chuen Khor, Yin Bun Cheung, Balram Chowbay
BACKGROUND: Genetic variants of TPMT and NUDT15 have been reported to predict the inter-patient variability in response and toxicity profiles of patients receiving thiopurine therapy. However, the clinical utility of TPMT genotyping in guiding thiopurine doses has been questionable, in part due to underlying differences in the prevalence of TPMT variants in both Caucasian and Asian populations. Several NUDT15 variants have been associated with thiopurine-induced leukopenia, particularly in Asian cohorts...
December 6, 2017: Pharmacogenomics
https://www.readbyqxmd.com/read/29206869/measurements-of-6-thioguanine-nucleotide-levels-with-tpmt-and-nudt15-genotyping-in-patients-with-crohn-s-disease
#3
Ji Hyeon Lee, Tae Jun Kim, Eun Ran Kim, Sung Noh Hong, Dong Kyung Chang, Li-Hwa Choi, Hye In Woo, Soo-Youn Lee, Young-Ho Kim
The association between the 6-thioguanine nucleotide (6-TGN) level and clinical remission in Crohn's disease (CD) remains controversial. Thiopurine-induced leukopenia is a life-threatening complication of CD in Asians that was recently shown to strongly correlate with NUDT15 genetic variants. This study aimed to determine the relationship between thiopurine metabolite levels and therapeutic response, and to investigate the association of NUDT15, TPMT, and thiopurine metabolites with leukopenia in patients with CD...
2017: PloS One
https://www.readbyqxmd.com/read/29197117/addition-of-allopurinol-for-altering-thiopurine-metabolism-to-optimize-therapy-in-patients-with-inflammatory-bowel-disease
#4
Geoffrey C Wall, Hamid Muktar, Cassandra Effken, Pramod B Mahajan
Thiopurine drugs, including azathioprine and 6-mercaptopurine, are used commonly in patients with inflammatory bowel disease for maintenance of remission. Although generally well tolerated, adverse effects lead to discontinuation in a significant minority of patients. Pharmacogenomic studies have suggested that metabolic breakdown of azathioprine in an individual is genetically determined. Coupled with the fact that certain thiopurine metabolites, notably 6-thioguanine nucleotide and 6-methylmercaptopurine, are associated with antiinflammatory effects and adverse effects, respectively, some investigators have examined intentionally shunting the metabolism of azathioprine toward increasing 6-thioguanine nucleotide levels by using low doses of the xanthine oxidoreductase inhibitor allopurinol to improve efficacy and decrease toxicity of azathioprine in patients with inflammatory bowel disease...
December 1, 2017: Pharmacotherapy
https://www.readbyqxmd.com/read/29192347/pharmacogenetics-of-thiopurines-for-inflammatory-bowel-disease-in-east-asia-prospects-for-clinical-application-of-nudt15-genotyping
#5
REVIEW
Yoichi Kakuta, Yoshitaka Kinouchi, Tooru Shimosegawa
The thiopurine drugs 6-mercaptopurine (6-MP) and azathiopurine (AZA) are widely used to treat inflammatory bowel disease. However, the incidence of adverse reactions is high, particularly in Asia, and the mechanisms of toxicity in Asian populations remain unclear. Thiopurine S-methyltransferase (TPMT) is a well-known enzyme that inactivates AZA or 6-MP through methylation and is one of the few pharmacogenetic predictors used in clinical settings in Western countries. Individuals carrying TPMT-deficient genetic variants require reduced drug doses, but this treatment modification is are not applicable to East Asian populations...
November 30, 2017: Journal of Gastroenterology
https://www.readbyqxmd.com/read/29147133/allopurinol-in-combination-with-thiopurine-induces-mucosal-healing-and-improves-clinical-and-metabolic-outcomes-in-ibd
#6
Brigitte Moreau, Pierre Clement, Yves Theoret, Ernest G Seidman
Background: Thiopurines, azathioprine (AZA) and 6-mercaptopurine (6-MP) are common maintenance medications for inflammatory bowel disease (IBD). Excessive methylation via thiopurine methyltransferase (TPMT) frequently causes therapeutic failure. Allopurinol reduces excessive 6-methyl-mercaptopurine (6-MMP) while enhancing 6-thioguanine (6-TGN) levels. The aim of this study was to evaluate clinical, metabolic and endoscopic impact of allopurinol in combination with low-dose thiopurine in IBD...
November 2017: Therapeutic Advances in Gastroenterology
https://www.readbyqxmd.com/read/29145599/a-role-for-thiopurine-metabolites-in-the-synergism-between-thiopurines-and-infliximab-in-inflammatory-bowel-disease
#7
Ditte V Mogensen, Jørn Brynskov, Mark A Ainsworth, Jacob Nersting, Kjeld Schmiegelow, Casper Steenholdt
Background: Interactions between principal cytotoxic thiopurine metabolites, 6-thioguanine nucleotides (6-TGN), and infliximab (IFX) and anti-IFX antibodies (Abs) may contribute to higher effectiveness of IFX-thiopurine-combination therapy than monotherapies in inflammatory bowel disease. Methods: To examine if thiopurine metabolites influenced trough IFX and anti-IFX Abs, 89 patients previously assessed for anti-IFX Abs were included. To assess if IFX influenced thiopurine metabolites, 8 patients having responded to 12 weeks of intensified IFX at a constant thiopurine dosing were included...
November 14, 2017: Journal of Crohn's & Colitis
https://www.readbyqxmd.com/read/29140288/capillary-electrophoresis-hyphenated-with-mass-spectrometry-for-determination-of-inflammatory-bowel-disease-drugs-in-clinical-urine-samples
#8
Katarína Maráková, Juraj Piešťanský, Zuzana Zelinková, Peter Mikuš
Azathioprine is the main thiopurine drug used in the treatment of immune-based inflammations of gastrointestinal tract. For the purpose of therapy control and optimization, effective and reliable analytical methods for a rapid drug monitoring in biological fluids are essential. Here, we developed a separation method based on the capillary electrophoresis (CE) hyphenated with tandem mass spectrometry (MS/MS) for the simultaneous determination of azathioprine and its selected metabolites (6-thioguanine, 6-mercaptopurine, and 6-methylmercaptopurine) as well as other co-medicated drugs (mesalazine, prednisone, and allopurinol)...
November 15, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/29120908/patients-beliefs-about-medicine-are-associated-with-early-thiopurine-discontinuation-in-patients-with-inflammatory-bowel-diseases
#9
Mark M T J Broekman, Marieke J H Coenen, Geert J Wanten, Corine J van Marrewijk, Wietske Kievit, Olaf H Klungel, André L M Verbeek, Dennis R Wong, Piet M Hooymans, Henk-Jan Guchelaar, Hans Scheffer, Luc J J Derijks, Marcel L Bouvy, Dirk J de Jong
BACKGROUND: Patients' beliefs about medicine may either reflect the necessity for treatment or concerns regarding the treatment. We explored the extent to which these beliefs have an effect on thiopurine metabolite levels and premature discontinuation in patients with inflammatory bowel disease (IBD). PATIENTS AND METHODS: Patients enrolled in the 'Thiopurine response Optimization by Pharmacogenetic testing in Inflammatory Bowel Disease Clinics' (TOPIC) trial were asked to complete the Beliefs about Medicine Questionnaire (BMQ) 4 weeks after thiopurine initiation...
November 15, 2017: European Journal of Gastroenterology & Hepatology
https://www.readbyqxmd.com/read/29051993/treatment-related-sinusoidal-obstruction-syndrome-in-children-with-de-novo-acute-lymphoblastic-leukemia-during-intensification
#10
Casey L McAtee, Netta Schneller, Julienne Brackett, M Brooke Bernhardt, Eric S Schafer
PURPOSE: Sinusoidal obstruction syndrome (SOS), also known as veno-occlusive disease, has been described following treatment of acute lymphoblastic leukemia (ALL) with the anti-metabolite 6-thioguanine (6-TG). Previous studies incorporating daily 6-TG into maintenance chemotherapy demonstrated a high incidence of SOS, typically presenting after prolonged exposures to 6-TG. 6-TG continues to be used as a single, 14-day burst during intensification; however, SOS associated with brief courses of 6-TG is poorly described...
October 19, 2017: Cancer Chemotherapy and Pharmacology
https://www.readbyqxmd.com/read/29040228/analytical-pitfalls-of-therapeutic-drug-monitoring-of-thiopurines-in-patients-with-inflammatory-bowel-disease
#11
Melek Simsek, Berrie Meijer, Chris J J Mulder, Adriaan A van Bodegraven, Nanne K H de Boer
The use of thiopurines in the treatment of inflammatory bowel disease (IBD) can be optimized by the application of therapeutic drug monitoring. In this procedure, 6-thioguanine nucleotides (6-TGN) and 6-methylmercaptopurine (6-MMP) metabolites are monitored and related to therapeutic response and adverse events, respectively. Therapeutic drug monitoring of thiopurines, however, is hampered by several analytical limitations resulting in an impaired translation of metabolite levels to clinical outcome in IBD...
December 2017: Therapeutic Drug Monitoring
https://www.readbyqxmd.com/read/28914560/thiopurine-metabolite-levels-in-patients-with-atopic-dermatitis-and-or-chronic-hand-foot-eczema-treated-with-azathioprine
#12
F M Garritsen, J van der Schaft, C A F Bruijnzeel-Koomen, R H van Schaik, M de Graaf, M P H van den Broek, M S de Bruin-Weller
BACKGROUND: Azathioprine is frequently used in severe eczema. It is converted in the liver into active metabolites, including 6-thioguanine nucleotide (6-TGN) and methylated 6-methylmercaptopurine (6-MMP). In the past, the therapeutic potential of azathioprine may have not been fully utilized. Recent investigations on inflammatory bowel disease have led to a better understanding of azathioprine metabolism and optimizing treatment. OBJECTIVE: To investigate whether measuring thiopurine metabolites in circulation can improve the effectiveness and safety of azathioprine treatment in patients with atopic dermatitis and/or chronic hand/foot eczema...
September 26, 2017: Journal of Dermatological Treatment
https://www.readbyqxmd.com/read/28877179/adherence-to-6-mercaptopurine-in-children-and-adolescents-with-acute-lymphoblastic-leukemia
#13
Mervat Alsous, Rana Abu Farha, Eman Alefishat, Suha Al Omar, Deema Momani, Alia Gharabli, James McElnay, Robert Horne, Rawad Rihani
OBJECTIVE: Studies on children with Acute Lymphoblastic Leukemia (ALL) reported non-adherence in 2-54% of cases. The primary objective of this study was to assess rates of adherence to 6-MP using two different methods in children and adolescents with ALL. Secondary aim was to identify factors that influence adherence to 6-MP in children with ALL. METHODS: All eligible children with ALL who are (≤ 19) years old and receive 6-MP therapy for at least 1 month were approached to participate in the study...
2017: PloS One
https://www.readbyqxmd.com/read/28839871/monitoring-thiopurine-metabolites-in-inflammatory-bowel-disease
#14
REVIEW
Yago González-Lama, Javier P Gisbert
Thiopurines (azathioprine and mercaptopurine) are one of the immunosuppressive mainstays for the treatment of inflammatory bowel disease. In spite of its widespread use, thiopurine metabolism is still not fully understood, and a significant proportion of patients suffer toxicity or lack of efficacy. Different enzymatic pathways with individual variations constitute a pharmacogenetic model that seems to be suitable for monitoring and therapeutic intervention. This review is focused on current concepts and recent research that may help clinicians to rationally optimise thiopurine treatment in patients with inflammatory bowel disease...
October 2016: Frontline Gastroenterology
https://www.readbyqxmd.com/read/28811125/pharmacokinetics-and-pharmacodynamics-of-thiopurines-in-an-in%C3%A2-vitro-model-of-human-hepatocytes-insights-from-an-innovative-mass-spectrometry-assay
#15
Marco Pelin, Elena Genova, Laura Fusco, Monzer Marisat, Ute Hofmann, Diego Favretto, Marianna Lucafò, Andrea Taddio, Stefano Martelossi, Alessandro Ventura, Gabriele Stocco, Matthias Schwab, Giuliana Decorti
AIM: To apply an innovative LC-MS/MS method to quantify thiopurine metabolites in human hepatocytes and to associate them to cytotoxicity. METHODS: Immortalized human hepatocytes (IHH cells) were treated for 48 and 96 h, with 1.4 × 10(-4) M azathioprine and 1.1 × 10(-3) M mercaptopurine, concentrations corresponding to the IC50 values calculated after 96 h exposure in previous cytotoxicity analysis. After treatments, cells were collected for LC-MS/MS analysis to quantify 11 thiopurine metabolites with different level of phosphorylation and viable cells were counted by trypan blue exclusion assay to determine thiopurines in vitro effect on cell growth and survival...
September 25, 2017: Chemico-biological Interactions
https://www.readbyqxmd.com/read/28774547/american-gastroenterological-association-institute-technical-review-on-the-role-of-therapeutic-drug-monitoring-in-the-management-of-inflammatory-bowel-diseases
#16
REVIEW
Niels Vande Casteele, Hans Herfarth, Jeffry Katz, Yngve Falck-Ytter, Siddharth Singh
Therapeutic drug monitoring (TDM), which involves measurement of drug or active metabolite levels and anti-drug antibodies, is a promising strategy that can be used to optimize inflammatory bowel disease therapeutics. It is based on the premise that there is a relationship between drug exposure and outcomes, and that considerable inter-individual variability exists in how patients metabolize the drug (pharmacokinetics) and the magnitude and duration of response to therapy (pharmacodynamics). Therefore, the American Gastroenterological Association has prioritized clinical guidelines on the role of TDM in the management of inflammatory bowel disease...
September 2017: Gastroenterology
https://www.readbyqxmd.com/read/28740837/histological-remission-of-autoimmune-hepatitis-after-the-addition-of-allopurinol-and-azathioprine-dose-reduction
#17
Ana Luiza Vilar Guedes, Adriana Ribas Andrade, Vinicius Santos Nunes, Fabiana Roberto Lima, Evandro Sobroza de Mello, Suzane Kioko Ono, Débora Raquel Benedita Terrabuio, Eduardo Luiz Rachid Cançado
The standard therapy for some autoimmune diseases consists of a combination of corticosteroids and thiopurines. In non-responders to thiopurine drugs, the measurement of the metabolites of azathioprine, 6-thioguanine, and 6-methylmercaptopurine, can be a useful tool. The measurement has been used during the treatment of inflammatory bowel diseases and, less commonly, in autoimmune hepatitis. Many patients preferentially metabolize thiopurines to 6-methylmercaptopurine (6-MMP), which is potentially hepatotoxic, instead of 6-thioguanine, the active immunosuppressive metabolite...
April 2017: Autopsy & Case Reports
https://www.readbyqxmd.com/read/28731668/-azathioprine-induced-pancytopenia-case-series
#18
Cristina Martínez Faci, Ignacio Ros Arnal, José M Martínez de Zabarte Fernández, Jordi Sorribes Estorch, Mónica López Campos, Carmen Rodríguez-Vigil Iturrate
Azathioprine is an immunosuppressive drug that has shown effectiveness in inflammatory bowel disease treatment. Its metabolite, 6-mercaptopurine, is metabolized through thiopurine methyltransferase. Patients with low enzyme activity may have more frequent and severe side effects. The most common is leukopenia, and rarely pancytopenia. The thiopurine methyltransferase activity monitoring shows an individualized profile of enzymatic activity but it should not replace monitoring by performing serial blood counts...
August 1, 2017: Archivos Argentinos de Pediatría
https://www.readbyqxmd.com/read/28723860/higher-thioguanine-nucleotide-metabolite-levels-are-associated-with-better-long-term-outcomes-in-patients-with-inflammatory-bowel-diseases
#19
Andres J Yarur, Bilal Gondal, Ayal Hirsch, Britt Christensen, Russell D Cohen, David T Rubin
GOALS: The aim of this study was to assess whether sustained 6-thioguaninenucleotide (6-TGN) levels were associated with improved long-term outcomes in patients with inflammatory bowel diseases (IBD). BACKGROUND: Cross-sectional data have shown that thiopurine metabolites are correlated with clinical efficacy in patient receiving thiopurines for IBD but the role for serial measurements through treatment course is unclear. STUDY: We conducted a retrospective cohort study including patients with IBD on thiopurine monotherapy and had serial 6-TGN levels measured...
July 18, 2017: Journal of Clinical Gastroenterology
https://www.readbyqxmd.com/read/28650902/itpa-activity-in-adults-and-children-treated-with-or-without-azathioprine-relationship-between-tpmt-activity-thiopurine-metabolites-and-co-medications
#20
Antony Citterio-Quentin, Mustapha Moulsma, Marie-Paule Gustin, Roselyne Boulieu
BACKGROUND: The implication of inosine triphosphate pyrophosphatase (ITPA) on thiopurine drug response variability has been investigated but little data are available on its role on thiopurine metabolites. The ability of ITPA to modify the thiopurine metabolite levels is currently used to optimize azathioprine (AZA) therapy in relation to thiopurine S-methyltransferase (TPMT) activity, the aim of this study is to investigate ITPA phenotype in a large population and to evaluate the relation between ITPA and TPMT activities and thiopurine metabolites...
October 2017: Therapeutic Drug Monitoring
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