Azathioprine or mercaptopurine-induced acute pancreatitis is not a disease-specific phenomenon

Risk factors for drug-related acute pancreatitis: an analysis of the FDA adverse event reporting system (FAERS)

Objective: While several drugs have been linked to acute pancreatitis (AP), the AP-related risk of most drugs remains unclear. This study investigated the risk factors for drug-induced AP by analyzing a large dataset from the FDA Adverse Event Reporting System (FAERS). Methods: The reporting odds ratios (ROR) were used to assess the reports of drug-induced AP from the first quarter of 2004 to the second quarter of 2022. Single-factor, LASSO, and multi-factor regression analysis were performed to explore drug-related AP-related risk factors. Bonferroni correction was applied for the multiple comparisons performed. Results: A total of 264 drugs associated with AP, including antineoplastic drugs (35/264), antidiabetic drugs (28/264), antibacterial drugs (24/264), immunomodulatory drugs (11/264), antipsychotic drugs (6/264), and other drugs (160/264) were retrieved. Multi-factor analysis showed that males, age 41-54 years old, and 36 drugs, including Tigecycline, were risk factors for drug-related AP. The median time to drug-related AP onset was 31 days (interquartile range [IQR] 7-102 days) and about 75% of adverse events occurred within 100 days. Conclusion: These findings may help clinicians to identify drug-related AP at the early stage and can be used to inform future studies of drug-related AP pathogenesis.

Finding Predictors of Azathioprine-Induced Pancreatitis in Patients With Inflammatory Bowel Disease

OBJECTIVES

Azathioprine (AZA)-induced pancreatitis (AIP) is a common, idiosyncratic adverse effect whose incidence and risk factors data in inflammatory bowel disease (IBD) patients are not fully clarified. We aimed to establish the incidence, clinical course and identify risk factors for AIP.

METHODS

A retrospective study including all IBD patients on AZA between January 2013 and July 2020 was conducted. Patients with AIP were considered.

RESULTS

Azathioprine-induced pancreatitis occurred in 33 patients (7.5%; 442 patients on AZA). The mean time receiving AZA until AIP was 25 days, with a mean dose of 88 mg. All patients had a mild course of disease, which resolved with suspension of AZA and with no complications. Smoking (P = 0.02), single daily dose of AZA (P < 0.001), and concomitant budesonide (P = 0.001) were risk factors for AIP. In multivariate analysis, concomitant treatment with budesonide (odds ratio, 5.3; P = 0.002) and single daily dose of AZA (odds ratio, 3.8; P = 0.002) were the only predictors of AIP.

CONCLUSIONS

Although AIP was a relatively common adverse effect, it presented a mild course in all patients. Smoking, concomitant use of budesonide, and single-dose regimen of AZA should be avoided in IBD patients treated with AZA.

HLA-variants associated with azathioprine-induced pancreatitis in patients with Crohn's disease

The immunosuppressant drug azathioprine is associated with a 4% risk of acute pancreatitis in patients with inflammatory bowel disease (IBD). Studies have demonstrated an increased risk in carriers of HLA‐DQA1*02:01 and HLA‐DRB1*07:01. We investigated whether these human leukocyte antigen (HLA) types were associated with azathioprine‐induced pancreatitis also in Swedish patients with IBD, and whether the type of disease affected the association. Nineteen individuals with IBD who developed acute pancreatitis after initiation of azathioprine were genotyped and compared with a population control cohort (n = 4891) and a control group matched for disease (n = 81). HLA‐DQA1*02:01 and HLA‐DRB1*07:01 were in full linkage disequilibrium, and were significantly associated with acute pancreatitis both when cases were compared with population controls (OR 3.97 [95% CI 1.57–9.97], p = 0.0035) and matched controls (OR 3.55 [95% CI 1.23–10.98], p = 0.0275). In a disease‐specific analysis, the correlation was positive in patients with Crohn's disease versus matched controls (OR 9.27 [95% CI 1.86–46.19], p = 0.0066), but not in those with ulcerative colitis versus matched controls (OR 0.69 [95% CI 0.07–6.74], p = 0.749). In patients with Crohn's disease, we estimated the conditional risk of carriers of HLA‐DQA1*02:01‐HLA‐DRB1*07:01 to 7.3%, and the conditional risk of a non‐carrier to 2.2%. We conclude that HLA‐DQA1*02:01‐HLA‐DRB1*07:01 is a marker for increased risk of acute pancreatitis in individuals of Swedish genetic origin, treated with azathioprine for Crohn's disease.

Characteristics and Frequency of Pediatric Inflammatory Bowel Disease-Associated Pancreatitis: A Japanese Nationwide Survey

Acute pancreatitis (AP) develops in approximately 2% of patients with the diagnosis of inflammatory bowel disease (IBD), but the characteristics and frequency of childhood-onset IBD-associated AP in Japan have not been studied. The present study aimed to clarify the characteristics of IBD-associated AP in Japan.

Methods

A nationwide survey of pediatric patients with IBD (age, <17 years) was conducted from December 2012 to March 2013 at 683 hospitals and medical centers in Japan. A secondary survey was also sent to the centers with the target patients to evaluate their characteristics.

Results

The response rate to the first part of the survey was 61.2% (n = 418). In total, 871 patients with Crohn disease and 1671 patients with ulcerative colitis were enrolled. The second part of the survey found that 11 (1.3%) patients with Crohn disease and 23 (1.4%) patients with ulcerative colitis experienced IBD-associated AP caused by medication (n = 18, 53%), a primary disease (n = 11, 32%), autoimmune pancreatitis (n = 1, 3%), or an anatomical abnormality (n = 1, 3%). All the patients had only mild AP.

Conclusions

IBD-associated AP was not very frequent and was generally mild. The major cause of the pancreatitis was the medication used to treat the IBD.

TPMT and NUDT15 polymorphisms in thiopurine induced leucopenia in inflammatory bowel disease: a prospective study from India

BACKGROUND

Polymorphisms in thiopurine methyltransferase (TPMT) and Nudix hydrolase-15 (NUDT15) have been implicated as the predominant cause of thiopurine induced leukopenia in the Western countries and East Asia respectively. Exact role of these polymorphisms in South Asian population with inflammatory bowel disease (IBD) is uncertain.

METHODS

We included consecutive patients with IBD who were initiated on thiopurines at a center in North India. The dosage of thiopurines was titrated using regular monitoring of hemogram and liver function tests. Three TPMT polymorphisms (c.238 G > C, c.460 G > A, and c.719A > G) and one NUDT15 polymorphism (c.415 C > T) were assessed. Comparison regarding incidence of leukopenia and maximum tolerated thiopurine dosage was performed between those with wild polymorphism and those with TPMT and NUDT15 polymorphisms, respectively.

RESULTS

Of the 119 patients (61 males, mean age 36.8 ± 13.5 years), 105 (88.2%) had ulcerative colitis and 14 (11.8%) had Crohn's disease. Leukopenia was noted in 33 (27.7%), gastrointestinal intolerance in 5 (4.2%) and pancreatitis in 2 (1.6%). TPMT polymorphisms were detected amongst five patients of whom 1 developed leukopenia. NUDT15 polymorphism was noted in 13 patients of whom 7 had leukopenia. The odds of developing leukopenia in TPMT polymorphism were non-significant (0.77, 95% CI:0.0822 to 7.2134, P = 0.819) but were significantly higher in those with NUDT15 polymorphism (3.5933, 1.1041 to 11.6951, P value: = 0.0336).

CONCLUSION

NUDT15 polymorphism was more frequent than TPMT polymorphisms and was associated with thiopurine induced leukopenia. However, the tested polymorphisms account for only 24.2% of the risk of thiopurine induced leukopenia.

Pancreatic Disorders in Children with Inflammatory Bowel Disease

Background and Objectives: Inflammatory bowel disease (IBD) is a chronic condition and mainly affects the intestines, however, the involvement of the other organs of the gastrointestinal tract (upper part, pancreas, and liver) have been observed. The coexistence of IBD with pancreatic pathology is rare, however, it has been diagnosed more frequently during recent years in the pediatric population. This article reviews the current literature on the most common pancreatic diseases associated with IBD in the pediatric population and their relationship with IBD activity and treatment. Materials and Methods: We performed a systematic review of data from published studies on pancreatic disorders, also reported as extraintestinal manifestations (EIMs), among children with IBD. We searched PubMed and Web of Science to identify eligible studies published prior to 25 April 2020. Results: Forty-four papers were chosen for analysis after a detailed inspection, which aimed to keep only the research studies (case control studies and cohort studies) or case reports on children and only those which were written in English. The manifestations of IBD-associated pancreatic disorders range from asymptomatic increase in pancreatic enzymes activity to severe disease such as acute pancreatitis. Acute pancreatitis (AP) induced by drugs, mainly thiopurine, seems to be the most- often-reported pancreatic disease associated with IBD in children. AP associated with other than drug etiologies, and chronic pancreatitis (CP), are rarely observed in the course of pediatric IBD. The pancreatic involvement can be strictly related to the activity of IBD and can also precede the diagnosis of IBD in some pediatric patients. The course of AP is mild in most cases and may occasionally lead to the development of CP, mainly in cases with a genetic predisposition. Conclusions: The involvement of the pancreas in the course of IBD may be considered as an EIM or a separate co-morbid disease, but it can also be a side effect of IBD therapy, therefore a differential diagnosis should always be performed. As the number of IBD incidences with concomitant pancreatic diseases is constantly increasing in the pediatric population, it is important to include pancreatic enzymes level measurement in the workup of IBD.

Inflammatory Bowel Diseases Elevate the Risk of Developing Acute Pancreatitis: A Meta-analysis

OBJECTIVES

Increasing data suggest that acute pancreatitis (AP) occurs more frequently among patients with inflammatory bowel diseases (IBDs) than in the non-IBD population; however, currently no comprehensive meta-analysis is available.

METHODS

Systematic literature search was conducted in 4 major databases. We included observational studies sampling from the general population. Basic study characteristics and crude incidences of AP were extracted. Pooled odds ratios (ORs) with 95% confidence interval (CIs) were calculated using the random-effects model. Subgroups were set up by Crohn disease and ulcerative colitis. Heterogeneity was tested with I statistics.

RESULTS

Eight studies were eligible for the analysis. The odds of AP were 3 times higher in IBD (OR, 3.11; 95% CI, 2.93-3.30; I, 0.0%), significantly higher in Crohn disease than in ulcerative colitis (P < 0.001; OR, 4.12 vs OR, 2.61; I, 0.0%). The pooled annual incidence of AP in IBD was 210/100,000 person-years (95% CI, 84-392/100,000 person-years; I, 98.66%).

CONCLUSIONS

We confirmed that IBD elevates the risk of AP and of 100,000 IBD patients 210 AP cases are to be expected annually. Therefore, it is important to include pancreatic enzyme level measurements and radiological investigations in the workup of IBD patients with acute abdominal pain.

The continuous rediscovery and the benefit-risk ratio of thioguanine, a comprehensive review

Introduction: In the 1950s, thioguanine (TG), a thiopurine-derivative together with azathioprine (AZA) and mercaptopurine (MP), were developed for the treatment of childhood leukemia. Over the years, the use of TG was also explored for other, mainly immune-mediated and inflammatory, diseases such as in the field of dermatology and rheumatology (e.g. psoriasis, systemic lupus erythematosus (SLE)) and gastroenterology and hepatology (e.g. inflammatory bowel diseases (IBD), autoimmune hepatitis).Areas covered: This review provides a comprehensive overview of all the clinical uses of TG and describes its mechanism of action, pharmacokinetic/pharmacodynamic features, and toxicity.Expert opinion: Thioguanine has shown beneficial clinical effects in hematological (particularly leukemia) and several immune-inflammatory diseases including psoriasis, SLE, polycythemia vera, Churg-Strauss syndrome, IBD, collagenous sprue, refractory celiac disease, and autoimmune hepatitis. Thioguanine is not effective in treating solid-cancers. At relatively low dosages, i.e. 0.2- 0.3mg/kg/day or 20 mg/day, TG has a favorable risk-benefit ratio and is a safe and effective drug in the long-term treatment of amongst other IBD patients. Thioguanine toxicity, especially myelotoxicity, and hepatotoxicity, including nodular regenerative hyperplasia (NRH) of the liver, is limited when dosed adequately. The occurrence of NRH appears dose-dependent and has been especially described during high dose TG above 40 mg/day.

Vedolizumab-induced acute pancreatitis: the first reported clinical case

Drug-induced acute pancreatitis (DIAP) is a rare, but clinically significant diagnosis. Vedolizumab, an α₄β₇ integrin inhibitor, which was approved in 2015 for treatment of moderate to severe inflammatory bowel disease, is a well-tolerated medication with a favourable safety profile and minimal serious adverse events in premarketing clinical trials. We present the first reported case of acute pancreatitis directly attributable to vedolizumab.

Clinical course of ulcerative colitis patients who develop acute pancreatitis

AIM

To investigate the clinical course of ulcerative colitis (UC) patients who develop acute pancreatitis.

METHODS

We analyzed 3307 UC patients from the inflammatory bowel disease registry at Asan Medical Center from June 1989 to May 2015. The clinical course of UC patients who developed acute pancreatitis was compared with that of non-pancreatitis UC patients.

RESULTS

Among 51 patients who developed acute pancreatitis, 13 (0.40%) had autoimmune, 10 (0.30%) had aminosalicylate-induced, and 13 (1.73%) had thiopurine-induced pancreatitis. All 13 patients with autoimmune pancreatitis (AIP) had type 2 AIP. Two (15.4%) patients had pre-existing AIP, and three (23.1%) patients developed AIP and UC simultaneously. Compared to non-pancreatitis patients, AIP patients had UC diagnosed at a significantly younger age (median, 22.9 years vs 36.4 years; P = 0.001). AIP and aminosalicylate-induced pancreatitis patients had more extensive UC compared to non-pancreatitis patients. All patients with pancreatitis recovered uneventfully, and there were no recurrences. Biologics were used more frequently in aminosalicylate- and thiopurine-induced pancreatitis patients compared to non-pancreatitis patients [adjusted OR (95%CI), 5.16 (1.42-18.67) and 6.90 (1.83-25.98), respectively]. Biologic utilization rate was similar among AIP and non-pancreatitis patients [OR (95%CI), 0.84 (0.11-6.66)]. Colectomy rates for autoimmune, aminosalicylate-induced, and thiopurine-induced pancreatitis, and for non-pancreatitis patients were 15.4% (2/13), 20% (2/10), 15.4% (2/13), and 7.3% (239/3256), respectively; the rates were not significantly different after adjusting for baseline disease extent.

CONCLUSION

Pancreatitis patients show a non-significant increase in colectomy, after adjusting for baseline disease extent.

Acute pancreatitis as a complication of childhood cancer treatment

Acute pancreatitis (AP) is now well recognized as a possible complication of childhood cancer treatment, interrupting the chemotherapy regimen, and requiring prolonged hospitalization, possibly with intensive care and surgical intervention, thereby compromising the effect of chemotherapy and the remission of the underlying malignant disease. This review summarizes the current literature and presents the various etiological factors for AP during chemotherapy as well as modern trends in the diagnosis and therapy of AP in children.

Probing the Association of Pancreatitis in Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) has been increasingly diagnosed in children and adults. Similarly, acute and chronic pancreatitis are increasingly prevalent conditions with potentially devastating consequences. There is a growing body of literature linking these 2 conditions. The purpose of this review is to provide a comprehensive outline of the association between IBD and pancreatitis and to explore their putative pathophysiology. Based on the collective reports, 2 outstanding reasons for pancreatitis in patients with IBD are medications and IBD complications.

Inflammatory Bowel Disease and Pancreatitis: A Review

BACKGROUND AND AIMS

Pancreatic abnormalities are common in inflammatory bowel disease (IBD) patients and represent a heterogeneous group of conditions that include acute pancreatitis, chronic pancreatitis, autoimmune pancreatitis and asymptomatic abnormalities. We sought to review the available evidence concerning the aetiology, clinical presentation, diagnosis and treatment of pancreatic conditions in IBD patients.

METHODS

A PubMed/Medline query was conducted addressing pancreatic disorders in IBD. Reference lists from studies selected were manually searched to identify further relevant reports. Relevant manuscripts about pancreatic disorders in patients with IBD were selected and reviewed.

RESULTS

Thiopurines and gallstones are the most frequent causes of acute pancreatitis in IBD patients. Thiopurine-induced acute pancreatitis is usually uncomplicated and self-limited. Some evidence suggests that chronic pancreatitis may be more common in IBD. Most cases are idiopathic, affecting young males and patients with ulcerative colitis. Autoimmune pancreatitis is a relatively newly recognized disease and is increasingly diagnosed in IBD, particularly for type 2 autoimmune pancreatitis in ulcerative colitis patients. Asymptomatic exocrine insufficiency, pancreatic duct abnormalities and hyperamylasaemia have been identified in up to 18% of IBD patients, although their clinical significance and relationship with IBD remain undefined.

CONCLUSIONS

The wide spectrum of pancreatic manifestations in IBD is growing and may represent a challenge to the clinician. A collaborative approach with a pancreas specialist may be the most productive route to determine aetiology, guide additional diagnostic workup, illuminate the aetiology and define the treatment and follow-up of these patients.

Pancreatic involvement in pediatric inflammatory bowel diseases

BACKGROUND

Inflammatory bowel diseases (IBDs) are a group of chronic diseases affecting the gastrointestinal tract, with a disabling course. The incidence of IBDs is increasing in different geographical areas, indicating its emergence as a global disease, especially in children. Many patients with IBDs develop extraintestinal manifestations (EIMs) during follow-up, as IBDs have a potential risk of systemic involvement..

DATA SOURCES

A systematic review of the literature was made to analyze latest studies on pancreatic involvement in children with IBD including our experience in assessing possible implications and its future application.

RESULTS

The involvement of the hepatobiliary system is considered a rare EIM of children with IBD, with an incidence much higher than that in the general population. Isolated pancreatic hyperenzymemia, which occurs in the absence of typical symptoms and/or characteristic imaging findings, may be found in many patients with IBD. The frequent causes of pancreatitis are drugs, bilio-pancreatic disorders, immunologic disturbances and pancreatic auto-antibodies, although in some cases idiopathic forms have been described.

CONCLUSIONS

It is important to establish a correct diagnostic approach based on etiology and to assess the most appropriate therapeutic strategy, thus avoiding complications and improving the quality of life of children with IBD.

Successful Mercaptopurine Usage despite Azathioprine-Induced Pancreatitis in Paediatric Crohn's Disease

BACKGROUND

Azathioprine [AZA] and mercaptopurine [MP] are recommended for maintenance of steroid-free remission in children with Crohn`s disease [CD]. Azathioprine-induced pancreatitis, an idiosyncratic and major side effect, has been considered as an absolute contraindication for the use of a second thiopurine in IBD patients.

MATERIALS AND METHODS

We describe two children with CD in whom MP were successfully trialled after a confirmed azathioprine-induced pancreatitis, being well tolerated in both cases.

RESULTS

Two boys [13 and 10 years old] started exclusive enteral nutrition after diagnosis of moderate (Pediatric Crohn's Disease Activity Index [wPCDAI] = 45) and mild [wPCDAI = 35] CD. Both developed an acute mild to moderate pancreatitis after 2 and 3 weeks, respectively, of AZA treatment but recovered fully in hospital after AZA withdrawal. They started on MP treatment without any adverse effect. They were tested for the presence of polymorphisms 238G>C, 460G>A, and 719A>G in the TPMT gene and 94C>A and 21>C in the ITPase. Both patients were wild-type for all tested polymorphisms.

CONCLUSIONS

Azathioprine-induced acute pancreatitis should not be considered as an absolute contraindication for the use of MP. Further investigation is required to create a better understanding of the mechanism underlying the adverse events and to allow more possibilities for personalised therapy.

Clinical predictors of thiopurine-related adverse events in Crohn's disease

AIM: To determine the incidence and predictors of thiopurine-related adverse events.

METHODS: Subjects with Crohn’s disease who were followed in the Alberta Inflammatory Bowel Disease Consortium patient database registry were identified. Retrospective chart review was conducted between August 5^th, 2010 and June 1^st, 2012. We collected data on: age at diagnosis; sex; disease location and behaviour at time of prescribing thiopurine; perianal fistulising disease at or prior to thiopurine prescription; smoking status at time of thiopurine prescription, use of corticosteroid within 6 mo of diagnosis; dosage, age at onset, and cessation of 5-aminosalicyclic acid (5-ASA); anti-tumour necrosis factor medication exposure and intestinal resection before thiopurine prescription. The primary outcome of interest was the first adverse event that led to discontinuation of the first thiopurine medication used. Logistic regression models were used to associate clinical characteristics with outcomes after adjusting for potential confounders. Risk estimates were presented as odds ratios (OR) with 95% CI. Effect modification by age and sex were explored.

RESULTS: Our cohort had a median follow-up duration of 5.8 years [interquartile range (IQR 25^th-75^th) 2.7-9.1]. Thiopurine therapy was discontinued in 31.3% of patients because of: hypersensitivity reactions (7.1%), acute pancreatitis (6.2%), gastrointestinal intolerance (5.4%), leucopenia (3.7%), hepatotoxicity (3.4%), infection (1.1%) and other reasons (4.3%). A higher incidence of thiopurine withdrawal was observed in patients over the age of 40 (39.4%, P = 0.007). A sex-by-age interaction (P = 0.04) was observed. Females older than 40 years of age had an increased risk of thiopurine discontinuation due to an adverse event (age above 40 vs age below 40, adjusted OR = 2.8; 95%CI: 1.4-5.6). In contrast, age did not influence thiopurine withdrawal in males (age above 40 vs below 40, adjusted OR = 0.9; 95%CI: 0.4-2.1). Other clinical variables (disease location and phenotype, perianal disease, smoking history, history of intestinal resection and prior 5-ASA or corticosteroid use) were not associated with an increased risk an adverse event leading to therapy cessation.

CONCLUSION: Thiopurine withdrawal due to adverse events is commoner in women over the age of 40 at prescription. These findings need to be replicated in other cohorts.

Crohn's disease outcome in patients under azathioprine: a tertiary referral center experience

BACKGROUND AND AIMS

Azathioprine is of major importance in the treatment of Crohn's disease; its efficacy has been showed in several works, but real-life data regarding its use is scarce. Our aim was to address the outcome of patients with Crohn's disease under azathioprine in the real-life setting.

METHODS

Crohn's disease patients followed at an Inflammatory Bowel Disease Outpatient Clinic under azathioprine were consecutively enrolled, being allocated in one of four groups. Two groups included patients on treatment with this drug, regarding its two major indications - prevention of post-operative recurrence and steroid-dependent disease; a third group included patients who needed infliximab in addition to azathioprine and a fourth group comprised patients who did not tolerate azathioprine.

RESULTS

A total of 221 patients were enrolled, 180 on azathioprine due to steroid-dependency (64 needing additional treatment with infliximab) and 41 for prevention of post-operative recurrence. Steroid-free remission was obtained in 48%. Immunosuppression decreased the number of hospitalized patients (64% vs 36%; p<0.001), but not the surgery rates per person per year. Azathioprine as a post-operative drug was effective in decreasing hospitalizations. The addition of infliximab decreased the number of patients hospitalized (p=0.009) and hospitalization rates per person per year (p<0.001), but had no effect in the surgery rates per person per year. Sixty patients (23%) experienced adverse effects with AZA, 39 requiring discontinuation of the drug.

CONCLUSIONS

In this real-life study, azathioprine had a long-term steroid sparing effect and reduced hospitalizations. Combination with infliximab reduced hospitalizations but did not decrease the surgery rate.

Crohn's disease with special symptoms as initial manifestations: Report of two cases

Crohn's disease is a chronic granulomatous inflammatory disorder of unknown pathogenesis. It can affect the whole digestive tract from the mouth to the anus, but the lesion is mostly located in the terminal ileum and the adjacent colon. Typical symptoms are abdominal pain and diarrhea, but there exist some cases with special symptoms as initial manifestations. Here we report two such cases.

Drug-induced acute pancreatitis: results from the hospital-based Berlin case-control surveillance study of 102 cases

BACKGROUND

Drug toxicity is a well-known cause of acute pancreatitis (AP). Although many drugs have been associated with AP, the magnitude of the risk of most of them remains largely unknown.

AIM

To determine the pancreatotoxic risk of a wide range of drugs.

METHODS

The hospital-based Berlin case-control surveillance study, including all 51 Berlin hospitals in a hospital network, ascertained 102 cases with idiopathic AP (IAP) and 750 controls between 2002 and 2011. Patients with IAP were thoroughly validated using anamnestic, clinical or laboratory data. Drug exposure was obtained in a face-to-face interview. Possible drug aetiology was assessed in individual patients through a standardised causality assessment applying the criteria of the World Health Organization. Drug risks were further quantified [odds ratios (OR) with 95% confidence intervals (CI)] in a case-control design with unconditional logistic regression analysis.

RESULTS

The pancreatotoxic risk of several drugs, including azathioprine (OR 5.1; 95% CI 1.9-13.5), fenofibrate (OR 12.2; 95% CI 2.3-69.1), mesalazine (OR 3.3; 95% CI 1.1-9.5) or angiotensin-converting enzyme inhibitors, was corroborated by case-control analysis and causality assessment. Causality assessment suggested a pancreatotoxic potential, among others, for mercaptopurine or the seldom reported leflunomide, and alluded to a novel risk for tocilizumab. Case-control analysis showed an increased risk for two phytotherapeutics: harpagophytum and valerian radix.

CONCLUSIONS

Our study quantified the pancreatotoxic risk of different drugs and phytotherapeutics. The findings corroborate previous results from the literature but also indicate risks for substances not previously reported, highlighting the need for further controlled studies on pancreatic toxicity.

Tioguanine in the treatment of refractory coeliac disease--a single centre experience

BACKGROUND

Refractory coeliac disease type I is a complicated form of coeliac disease characterised by primary or secondary resistance to a gluten-free diet with persisting or reoccurring intestinal villous atrophy and symptoms of malabsorption. Besides corticosteroids, azathioprine has been advocated for the treatment of refractory coeliac disease type I. However, tioguanine (TG) might be better tolerated and more efficacious owing to a simpler metabolism towards bioactivation.

AIM

To evaluate tolerability and effectiveness of the nonconventional thiopurine derivative TG in refractory coeliac disease type I.

METHODS

Refractory coeliac disease type I patients treated with TG between June 2001 and November 2010 with a follow-up period of at least 1 year were included. Adverse events, laboratory values, 6-thioguanine nucleotide concentrations and rates of both clinical and histological response were evaluated at baseline and during follow-up.

RESULTS

Twelve adult refractory coeliac disease type I patients were included. The median TG treatment duration was 14 months. Ten patients tolerated TG treatment on the long term, whereas two patients withdrew treatment due to adverse events. No nodular regenerative hyperplasia of the liver was observed. During follow-up clinical and histological response was observed in 83% and 78%, respectively. Corticosteroid dependency decreased by 50%.

CONCLUSION

Tioguanine appears to be a convenient drug for the treatment of refractory coeliac disease type I based on higher histological and similar clinical response rates as compared with historical conventional therapies.

Difficulties and possibilities with thiopurine therapy in inflammatory bowel disease--proceedings of the first Thiopurine Task Force meeting

BACKGROUND

Thiopurines, such as azathioprine and mercaptopurine, are of pivotal importance in the treatment of inflammatory bowel disease. Although these drugs have been used for several decades, still many questions remain unanswered.

AIM

To provide an overview of clinically and scientifically challenging topics concerning thiopurine therapy in inflammatory bowel disease treatment.

METHODS

The first meeting of the Thiopurine Task Force Interest Group was held during the 2009 United European Gastroenterology Week in London (GASTRO2009). The topics of this meeting were of particular clinical and scientific interest. Additional literature was identified by performing a Pubmed search using the search terms 'inflammatory bowel disease', 'azathioprine', '6-mercaptopurine' and 'thioguanine'.

RESULTS

The following topics were discussed: therapeutic drug monitoring; the synergy of thiopurines with aminosalicylates and allopurinol; serious adverse events such as opportunistic infections, hepatotoxicity, carcinogenicity and pancreatitis; prolongation of thiopurines during clinical remission; indications for thiopurines in the postoperative setting; and the potential use of thioguanine. Specific interesting and clinically relevant topics for potential future research are provided.

CONCLUSIONS

Thiopurines remain central to inflammatory bowel disease treatment, although future studies are required to substantiate a more personalised medicine approach to their use.

Thiopurines in Crohn's disease, is there something new?

IMPORTANCE OF THE FIELD

traditional immunosuppressants, including azathioprine, remain the mainstay of therapy in steroid dependent/refractory patients with inflammatory bowel diseases (IBD). The main limitations of its use are its side effects appearing in about a fifth of the patients, including myelosuppression and liver toxicity. Major complications occur in patients with low thiopurine-S-methyltransferase (TPMT) enzyme activity; however, the clinical relevance of these tests remains conflictive.

AREAS COVERED IN THIS REVIEW

in this review, the authors aim to summarize the new data regarding the relationship between the pharmacology of thiopurines and pathogenesis of adverse events.

WHAT THE READER WILL GAIN

readers will gain an understanding of the metabolism of thiopurines, side effect profile, pharmacological background of side effects, importance of metabolite monitoring, clinical relevance of inherited differences in drug metabolism and other conditions (e.g., concomitant use of allopurinol) which can modify enzyme activity. By gaining an understanding of the pharmacology and metabolism of thiopurines, clinicians will be able to optimize thiopurine therapy in IBD.

TAKE HOME MESSAGE

TPMT testing and metabolite monitoring are still not considered the standard of care, and clinicians will continue to choose the approach that best suits their clinical practice and patient needs. Regardless of what strategy is chosen, patients need to be carefully monitored and well informed about the potential risks.