The U.S. Food and Drug Administration says warnings to drug companies regarding misleading advertisements have more than tripled in the last year.

Thomas Abrams, head of FDA's Division of Drug Marketing and Communications says, the agency sent 17 warning letters in the 12 months ending in August compared with an average of about four to five letters in recent years.

The majority of the 17 letters, about 82-percent, cited companies for not including information about side effects and other risks in promotional materials for patients or doctors.

Abrams says, "Industry can make efforts to better present risk information. This is critical to public health."