Off label

The use of colchicine for gout is FDA approved, whereas the use of colchicine for pericarditis is off label (but is widely respected).

Off label use of colchicine for pericarditis is widely respected.

Use of a strong opioid such as fentanyl for mild headache is not only off label but also unprofessional.

While the drug is approved for use in treating stomach cancer, many doctors prescribe it off label for other cancers as well.