Aug. 15, 2007 -- Drug ads are increasingly taking up a bigger portion of drug companies' advertising budgets, a new study shows.

The study, published in The New England Journal of Medicine, is based on data from the U.S. pharmaceutical industry.

The researchers included Julie Donohue, PhD, of the University of Pittsburgh's department of health policy and management.

They compared drug companies' 1996 and 2005 spending for direct-to-consumer drug ads shown on TV and web sites, played on radio stations, and placed in magazines and newspapers.

The study shows that in 2005, drug companies spent 330% more on direct-to-consumer drug ads than in 2006.

Even so, drug companies still spend more promoting drugs directly to health care professionals, according to the study.

Overall, drug companies spent $11.4 billion to promote their drug products in 1996, compared to $29.9 billion in 2005. "Although during that time spending on direct-to-consumer advertising increased by 330%, it made up only 14% of total promotional expenditures in 2005," Donohue's team writes.

The researchers also report that the number of letters sent by the FDA to drugmakers about violations of drug-advertising regulations fell from 142 letters in 1997 to 21 letters in 2006.

"This decline may reflect either better industry compliance with advertising regulations or a worsening of FDA oversight," write Donohue and colleagues.

The researchers didn't have data on every drug on the market.

In the journal, Donohue reports receiving consulting fees from the drug company GlaxoSmithKline and CanWest Global Communications, a Canadian media company.