RPS advice reminds prescribers to consider that specials have not been assessed by the regulatory authority for safety, quality and efficacy in the same way that licensed medicine has. As different specials manufacturers will formulate products in different ways, there is the potential for variation in bioavailability, consistency and quality. Nor is it likely a patient information leaflet will be available.8

In addition, prescribers “must be satisfied that there is sufficient evidence or experience of using the medicine to demonstrate its safety and efficacy.” The BAD guidance recognises that the evidence base for many dermatology specials used for more than 50 years is “entirely empirical and clinical trials will never be carried out.”8,9

Side effects are another issue. A review of unlicensed medicines usage, including specials medicines and licensed medicines used off label, found a number of studies pointing to increased potential for adverse drug reactions. Many of the studies looked at the potential for ADRs in children prescribed an unlicensed medicine, but there was very little data for adults.11