The article reflects on the use of risk assessment in preparing to introduce a new therapy in a patient with a concurrent diagnosis of Crohn's disease and multiple sclerosis. It reflects upon the process by which the author considered the prescribing of azathioprine and allopurinol (as a combination therapy) as an alternative to introducing infliximab—a biological therapy—for the management of patients with Crohn's disease. Particular emphasis is placed on the undertaking of a risk assessment, the implementation of therapy change, and the impact on the author's role as an advanced practitioner.