Off‐label prescriptions of drugs used for the treatment of Crohn's disease or ulcerative colitis.

Background: Off‐label prescribing is encountered across various fields of medicine and creates alternative treatment options, but is associated with unknown safety risks. The use of off‐label drugs for the treatment of patients with inflammatory bowel diseases (IBD) has not been characterised before. Aim: To assess the proportion and characteristics of off‐label prescribing for IBD in tertiary care centres in the Netherlands. Methods: A prospective database of IBD patients from all Dutch university hospitals was used to collect data on drug prescriptions for IBD and demographics. Drugs were classified as off‐label if they were unlicensed for Crohn's disease and/or ulcerative colitis by the Medicines Evaluation Board. Uni‐ and multivariable analyses were used to identify patient‐specific characteristics predictive of increased off‐label use. Results: For the induction and/or maintenance treatment of 4583 IBD patients, 12 651 historical and current drug records were available in the database. Of these, 2374 (19%) were considered off‐label prescriptions. Out of 4583 IBD patients, 1477 (32%) were exposed to off‐label drugs. Commonly prescribed off‐label IBD drugs were mercaptopurine (18%), beclomethasone (12%), thioguanine (4%) and allopurinol (3%). Non‐thiopurine/methotrexate off‐label drugs were prescribed in 243 patients (6%), including biological agents or tofacitinib in 47 IBD patients (1%). Off‐label prescriptions were more common in ulcerative colitis than Crohn's disease (37% vs 29%, P < 0.001). Smokers and patients that received ≥5 drug types during their disease course were more likely to be exposed to off‐label drugs (smoking 33% vs 27% and multiple drug use 66% vs 22%, both P < 0.001). Conclusion: About one‐fifth of prescriptions for IBD were off‐label and one‐third of IBD patients, especially ulcerative colitis patients, were exposed to off‐label drugs. [ABSTRACT FROM AUTHOR]