Patients with chronic myeloid leukaemia and chronic lymphocytic leukaemia are now predominantly managed in an outpatient setting, with infrequent need for hospital-based therapy. New targeted oral treatments have transformed survival outcomes. An increasing number of patients now have a life expectancy approaching that of the general population. Suboptimal drug adherence is common and a key reason for therapy failure and poor clinical outcomes. The pharmacokinetics of new oral targeted drugs are significantly impacted by drug–drug interactions and an altered gastric pH. Long-term use of some of the new oral drugs is associated with complications, including cardiovascular events and infections, which can be fatal if not recognised.