US and Canadian researchers found out that, even though direct-to-consumer advertising of prescription drugs continues to rise, it actually doesn’t encourage the consumers to buy the products.

They said that even though US companies spent an estimated $3 billion in 2005 and $5 billion in 2006 on such advertisements the result was not what they hoped for.

The opponents of the ads, who claimed that so much publicity can lead to drug overuse and misuse by impressionable patients urging their doctors to prescribe the drugs seen on TV, might have nothing to worry about.

The five-year study also implies that the pharmaceutical industry wastes about $4.8 billion each year, spending the shareholders’ money on the useless ads.

Most countries ban direct advertising of prescription medications, with the exceptions of the United States and New Zealand.

“People tend to think that if direct-to-consumer advertising wasn't effective, pharma wouldn't be doing it,” Harvard Medical School's Stephen Soumerai said in a statement, as quoted by Reuters. “But as it turns out, decisions to market directly to consumers are based on scant data.”

The study was conducted in Canada, and the researchers used French-speaking Quebec residents for their tests.

The reason behind this is that English-dominant Canadians see a lot of US advertising, while French-speaking Quebecois see far less and therefore, they are less likely to let themselves influenced by the ads, the study in the British Medical Journal reports.

The researchers based their study on three drugs: Enbrel (for rheumatoid arthritis), Nasonex (for nasal allergies) and Zelnorm (for irritable bowel syndrome). They checked whether the use of the drugs increased faster in the English-speaking regions following the ads’ release.

The results showed that prescription rates for Enbrel and Nasonex remained the same in both communities, while sales of Zelnorm increased for a short while in English-speaking regions, before going back down in a few years.