The move, which is part of a broader FDA effort to provide consumers with better, more understandable drug information, "can help promote greater consumer awareness about prescription drugs," said Michael J. Friedman, lead deputy FDA commissioner, in a statement.

But a leading consumer advocate warned that manufacturers will use the new advertising opportunities to sell consumers new, more profitable products when older drugs may work as well or better. "It is a setup for misleading people," said Sidney M. Wolfe, executive director of Public Citizen's Health Research Group.

Under the old guidelines, drug companies could say very little about prescription drugs in advertisements aimed at consumers. They were even prohibited from mentioning the condition a drug is intended to treat unless they were prepared to provide a great deal of additional information about the product, including all the possible side effects.