The First Amendment does not preclude drugmakers from FDA’s oversight of off-label communication even if what they say is truthful, the agency said.

The agency has the authority to regulate all off-label communication to ensure unapproved drugs do not reach the market, according to an FDA memo.

The FDA cannot explicitly restrict communication on off-label uses, but it has the power to regulate the introduction of unapproved or misbranded drugs and a company’s promotions might be relevant to enforcement.