No abstract

Immunomodulator drugs, of which thiopurines can be considered the backbone, are widely used in the treatment of inflammatory bowel disease. They have been shown to be highly effective and safe; however, a significant proportion of patients are deemed to have a poor response or suffer adverse reactions. Knowing how to monitor and optimize thiopurine therapy in these scenarios is crucial to effective management. We discuss the metabolism of thiopurines, the use of enzyme/metabolite testing to guide treatment, as well as strategies to circumvent toxicity and side effects, such as allopurinol coprescription. The indications, use in pregnancy, safety profile and duration of thiopurine therapy are also discussed.

Background: Thioguanine (TG) is efficacious in inflammatory bowel disease (IBD), but its toxicity, particularly nodular regenerative hyperplasia (NRH) of the liver, has limited its use. We assessed the long-term clinical outcomes and safety of TG in patients whom were intolerant or refractory to conventional immunomodulators. Methods: This is a retrospective, single-centre study of IBD patients treated with TG from 2001-2013. Response was defined as clinical remission (Harvey-Bradshaw Index < 5 for Crohn's disease (CD), Simple Clinical Colitis Activity Index < 4 for ulcerative colitis (UC)) without corticosteroids or, if receiving anti-tumour-necrosis-factor (anti-TNF) therapy, absence of dose escalation. We recorded TG failure, withdrawal and adverse events. Patients were monitored with biochemistry, liver biopsy and/or magnetic resonance imaging (MRI). Results: 54 patients (47 CD and 7 UC) whom received TG (mean dose: 27 mg/d (range: 20-40 mg/d)) as monotherapy (n ¼ 36) or concomitantly with anti-TNF (n ¼ 18) for a median inter-quartile range of 16 (5-37) months (126 patient-years of followup). 32 (59%) patients responded to TG at 6 months and 23 (43%) at 12 months. Pancreatitis did not recur amongst the 19 patients with prior thiopurine-induced pancreatitis. 16 (30%) patients ceased TG due to intolerance or toxicity (four serious); NRH was not observed. 6-thioguanine nucleotide concentrations did not correlate with efficacy nor with toxicity. Conclusions: TG was efficacious and well tolerated in one out of two patients who had previously failed conventional immunomodulators. NRH did not occur.

Budd-Chiari syndrome is a rare disorder characterised by hepatic venous outflow obstruction. It affects 1.4 per million people, and presentation depends upon the extent and rapidity of hepatic vein occlusion. An underlying myeloproliferative neoplasm is present in 50% of cases with other causes including infection and malignancy. Common symptoms are abdominal pain, hepatomegaly and ascites; however, up to 20% of cases are asymptomatic, indicating a chronic onset of hepatic venous obstruction and the formation of large hepatic vein collaterals. Doppler ultrasonography usually confirms diagnosis with cross-sectional imaging used for complex cases and to allow temporal comparison. Myeloproliferative neoplasms should be tested for even if a clear causative factor has been identified. Management focuses on anticoagulation with low-molecular-weight heparin and warfarin, with the new oral anticoagulants offering an exciting prospect for the future, but their current effectiveness in Budd-Chiari syndrome is unknown. A third of patients require further intervention in addition to anticoagulation, commonly due to deteriorating liver function or patients identified as having a poorer prognosis. Prognostic scoring systems help guide treatment, but management is complex and patients should be referred to a specialist liver centre. Recent studies have shown comparable procedure-related complications and long-term survival in patients who undergo transjugular intrahepatic portosystemic shunting and liver transplantation in Budd-Chiari syndrome compared with other liver disease aetiologies. Also, the optimal timing of these interventions and which patients benefit from liver transplantation instead of portosystemic shunting remains to be answered.