Read by QxMD icon Read

Thiopurine metabolites

Erik Munnig-Schmidt, Mei Zhang, Chris J Mulder, Murray L Barclay
Background: The thiopurines azathioprine and mercaptopurine remain pivotal maintenance treatments in inflammatory bowel disease (IBD); however, up to 15%-20% of patients preferentially produce the hepatotoxic metabolite 6-methylmercaptopurine (6MMP) at the expense of the therapeutic 6-thioguanine nucleotides (6TGN). This metabolic shunting usually begins within 3 months of therapy. We noted patients developing shunting many months or years after starting treatment and aimed to determine how often this late shunting occurs and whether this could be explained by patient factors or concomitant medications...
March 7, 2018: Inflammatory Bowel Diseases
Hlaing H Maw, Xingzhong Zeng, Scot Campbell, Mitchell E Taub, Aaron M Teitelbaum
BI 187004, an 11β-hydroxysteroid dehydrogenase 1 (HSD) inhibitor, was administered once daily for 14 days to eight patients with type 2 diabetes mellitus. N-methylation was identified as a major biotransformation pathway. In four patients treated with BI 187004, the plasma exposure of an N-methylbenzimidazole metabolite (M1) was 7 fold higher than the remaining four patients, indicating a substantial degree of metabolic variation. To identify the methyltransferase enzyme(s) responsible for N-methylation, BI 187004 was incubated with human liver microsomes (HLM), human kidney microsomes (HKM), and their respective cytosolic preparations in the presence and absence of isoform-selective chemical inhibitors...
March 7, 2018: Drug Metabolism and Disposition: the Biological Fate of Chemicals
A B Friedman, S J Brown, P Bampton, M L Barclay, A Chung, F A Macrae, J McKenzie, J Reynolds, P R Gibson, S B Hanauer, M P Sparrow
BACKGROUND: Thiopurine hypermethylation towards 6-methylmercaptopurine (6MMP) instead of 6-thioguanine nucleotides (6TGN) is associated with inefficacy in patients with IBD. Allopurinol reverses such hypermethylation. AIMS: To prospectively determine efficacy of allopurinol-thiopurine combination and to compare 2 doses of allopurinol. DESIGN: In a multicentre, double-blind trial, patients with clinically active or steroid-dependent IBD and thiopurine shunting were randomised to 50 or 100 mg/d allopurinol and 25% of their screening thiopurine dose, which was subsequently optimised, aiming for 6TGN of 260-500 pmol/8x108 RBCs...
February 21, 2018: Alimentary Pharmacology & Therapeutics
In Young Yoo, Kyunghoon Lee, Ok Ja Ji, Hye In Woo, Soo Youn Lee
Measurement of thiopurine metabolites is helpful to monitor adverse effects and assess compliance in patients on thiopurine treatment. The purpose of this study was to develop and validate an analytical method for measurement of thiopurine metabolites, thioguanine nucleotides (6-TGN) and 6-methylmercaptopurine nucleotide (6-MMPN), in RBCs. We developed and validated a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the quantification of 6-TGN and 6-MMPN and evaluated the stability of the thiopurine metabolites in RBC and whole blood states without any preprocessing at various storage conditions...
May 2018: Annals of Laboratory Medicine
Tina Gerbek, Maria Ebbesen, Jacob Nersting, Thomas L Frandsen, Malin Lindqvist Appell, Kjeld Schmiegelow
PURPOSE: To explore the levels of thioguanine incorporated into DNA (DNA-TG), and erythrocyte levels of 6-thioguanine nucleotides (Ery-TGN) and methylated metabolites (Ery-MeMP) during 6-mercaptopurine (6MP)/Methotrexate (MTX) therapy of childhood acute lymphoblastic leukemia (ALL) and the relation to inosine triphosphatase (ITPA) and thiopurine methyltransferase (TPMT) gene variants. METHODS: Blood samples were drawn during 6MP/MTX maintenance therapy from 132 children treated for ALL at Rigshospitalet, Copenhagen...
February 1, 2018: Cancer Chemotherapy and Pharmacology
V Guillotin, G Galli, J-F Viallard
Azathioprine is widely used in internal medicine and frequently implicated in occurrence of adverse events. Among these adverse events the bone marrow suppression, a dose-related one, is the most serious because of is potential morbidity and mortality. Severe myelosuppression, associated with abnormal AZA metabolism, is linked to the thiopurine methyltransferase (TPMT) genetic polymorphism that results in a high variability of its activity with 89% of patients with a normal activity, 11% with an intermediate activity, and 0...
January 19, 2018: La Revue de Médecine Interne
Fernando Bermejo, Mariam Aguas, María Chaparro, Eugeni Domènech, Ana Echarri, Esther Garcia-Planella, Iván Guerra, Javier P Gisbert, Antonio López-Sanromán
Thiopurines (azathioprine and mercaptopurine) are widely used in patients with inflammatory bowel disease. In this paper, we review the main indications for their use, as well as practical aspects on efficacy, safety and method of administration. They are mainly used to maintain remission in steroid-dependent disease or with ciclosporin to control a severe ulcerative colitis flare-up, as well as to prevent postoperative Crohn's disease recurrence, and also in combination therapy with biologics. About 30-40% of patients will not respond to treatment and 10-20% will not tolerate it due to adverse effects...
January 18, 2018: Gastroenterología y Hepatología
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
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...
January 2018: Pharmacogenomics
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
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...
February 2018: Pharmacotherapy
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...
February 2018: Journal of Gastroenterology
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
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
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
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...
February 2018: European Journal of Gastroenterology & Hepatology
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...
December 2017: Cancer Chemotherapy and Pharmacology
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
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
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
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"