According to the American Cancer Society, when a drug is used in a way that is different from that described in the FDA-approved drug label, it’s said to be an “off-label” use. This can mean that the drug is:
Used for a different disease or medical condition
Given in a different way (such as by a different route)
Given in a different dose than in the approved label
Drugs can also be used off-label in different populations than the one for which the label is indicated. This happens often in pediatric practice because children are too young to give informed consent, so do not participate in clinical trials. A pediatrician I know says when she prescribes off-label drugs, the drugs are often well-known “tried and true” treatments, and she is careful to evaluate the dosage and monitor her patients for adverse effects.