When a clinician prescribes a drug for any purpose or to a population other than what the U.S. Food and Drug Administration explicitly has approved and licensed that drug for, the medication is being used “off label,” literally a purpose not on the label issued by the FDA. Prescribing a drug off label is not illegal or even necessarily problematic. About half of all drugs prescribed to children are prescribed off label because no trials were conducted involving children, making it impossible for the FDA to approve the drug in that population. But decades of research on observational studies can be used to establish a drug’s safety and effectiveness either in new populations not included in clinical trials or for a new purpose. For example, many mood stabilizers prescribed off-label for bipolar disorder were originally licensed as anti-epileptic medications for those with epilepsy. But it’s important to note that a drug’s off-label use means the FDA itself has reviewed the evidence for that drug’s safety and effectiveness either in the population receiving it or to treat the condition they have.
