Ever since their introduction in 2006, there has been a growing number of biosimilars coming onto the European market – to date there are 22 authorised biosimilars. The European Medicines Agency (EMA) defines biosimilar medicine as ‘a biological medicine that is similar to another biological medicine that has already been authorised for use’. Hospital pharmacists are specialists in the science of complex therapeutic agents so are ideally placed to lead the way in introducing biosimilars into hospitals. Regulatory requirements for biosimilars differ from that of the reference product. The key thing for healthcare professionals to understand is the terminology used relating to the use of biosimilar medicines. Interchangeability is an EMA definition of two drugs being substituted for one another. Substitution is variable in each Member State. Biosimilarity does not imply interchangeability as it is not identical to the reference product and needs to be proven both ways. The way that the drug is produced determines the final product and introduces variation, hence the specific wording of the EMA definition of a biosimilar. There is a clear need for education in this area for all stakeholders, including policy-makers, patients, doctors and pharmacists. As the experts, pharmacists are key in leading the way to tackle this knowledge gap. The only information available on any given biosimilar is the EPAR, which is a complex document that is more than 50 pages long. This needs to be simplified for any clinicians who may not be sure about biosimilars. The only potential risk for switching to biosimilars is immunogenicity profiles of the drugs being enhanced. In theory, this is a small risk as the drug efficacy etc. has already been approved. In practice, no adverse events have been found in 10 years. However, the risk is proportional to the changes in manufacturing of a biosimilar that might occur. In the last issue of Hospital Pharmacy Europe we had an example of how switching to biosimilar infliximab can reap cost-saving benefits. But it is not the only selection criteria for introducing biosimilars to a hospital formulary. Each biosimilar has it’s own challenges in terms of uptake, evidence and education. Healthcare professionals need to come to grips with difficult concepts such as bioequivalence and biosimilarity. But the reason to have a biosimilar in a biosimilars is immunogenicity profiles of the drugs being enhanced. In theory, this is a small risk as the drug efficacy etc. has already been approved. In practice, no adverse events have been found in 10 years. However, the risk is proportional to the changes in manufacturing of a biosimilar that might occur. Hospital managers need to address the increased spending in hospitals and rising cost of medical treatment because it needs to be asked – is healthcare funding sustainable?