[Off-label prescription: practice and problems].

Approval of a drug for clinical use requires production of data on efficacy and safety through submission of results from randomized controlled trials (RCTs), in which the new molecule is usually compared with placebo (or an active comparator) for a set of outcomes that will serve as the basis for the drug's indications. These indications are crucial, because drugs are approved on the basis of their net clinical benefit for specific and well-defined diseases and--importantly--only for these. Once the drug is available for use in tens or hundreds of thousands of patients, physicians may realize that some medications can be effective in diseases for which they were not approved, i.e., no studies have been presented to the regulatory authorities, and therefore they are not formally approved for those indications. Convinced of the benefits for their patients, some physicians prescribe them for unapproved indications--off-label prescription. In this paper we discuss the prevalence of off-label prescription, and its advantages and problems.