INTRODUCTION Thiopurine therapy is often discontinued in inflammatory bowel disease (IBD) patients. The xanthine oxidase (XO) inhibitor allopurinol has previously shown to enhance thiopurine efficacy and to prevent adverse reactions, the mechanism of this beneficial interaction is not completely clarified. The aim of this study is to observe possible effects of allopurinol and low-dose thiopuri...

Background & Objective:  Thiopurine drugs are considered as a treatment modality in various autoimmune disorders including pemphigus vulgaris (PV). These drugs are metabolized by an enzyme “Thiopurine S-methyl transferase” (TPMT). Various variants of this enzyme may have decreased activity lead...

BACKGROUND Phase II biotransformation reactions (also 'conjugation reactions') generally serve as a detoxifying step in drug metabolism. Phase II drug metabolising enzymes are mainly transferases. This review covers the major phase II enzymes: UDP-glucuronosyltransferases, sulfotransferases, N-acetyltransferases, glutathione S-transferases and methyltransferases (mainly thiopurine S-methyl tran...

Background and aim: Azathioprine is the most widely used immunosuppressive agent as an adjunct to corticosteroids in the treatment of pemphigus vulgaris (PV). Thiopurine methyl transferase (TPMT) is a key enzyme in azathioprine metabolism and a genetic polymorphism controls its activity in human tissue. TPMT activity can provide a rational basis to determine suitable dose of azathioprine, theor...

Azathioprine is an immunomodulator commonly used in renal transplant recipients and to treat lupus erythematous, inflammatory bowel disease, as second-line therapy cases of rheumatoid arthritis. Here, we present a case non-segmental vitiligo treated with low-dose azathioprine developing life-threatening pancytopenia febrile neutropenia trephine biopsy-proven drug-induced myelosuppression. The p...

Acute lymphoblastic leukemia (ALL) is an aggressive hematological tumor resulting from the malignant transformation of lymphoid progenitors. Thiopurine is a widely used drug in the maintaining treatment of ALL. After a period of chemotherapy, 20% of pediatric patients and over 50% of adult patients will relapse. To investigate the mechanisms of drug resistance in vitro, we established the thiop...

Background: 6-Mercaptopurine (6-MP), a widely used anti-metabolite for the maintenance phase of childhood acute lymphoblastic leukemia (ALL), has been observed to cause myelotoxicity due genetic polymorphism thiopurine methyl transferase (TPMT), one drug-metabolizing enzymes. This study aimed determine frequency S-methyl (TPMT) polymorphic variants in group Pakistani children with (ALL) using 6...