Gauging the Impact of DTC Ads

Despite the estimated $5 billion that pharmaceutical companies spend on direct-to-consumer advertising, a recent study published in the British Journal of Medicine concludes that the ads may not make a lot of difference in drug sales. According to the study, ads for the allergy medication Nasonex and the rheumatoid arthritis drug Elbrex failed to move the prescription rate needle upwards after an ad campaign. There was a post-campaign spike in prescriptions for Zelnorm, a drug used to treat irritable bowel syndrome that has since been withdrawn from the market.

The study was unusual in its methodology because of the difficulty in finding the control group that would not be exposed to the DTC ads. The researchers decided to use Canadians as study subjects, since DTC ads are banned in Canada, but many Canadians are exposed to the advertising through US television broadcasts. They compared prescription rates for English-speaking Canadians, who are known to watch a great deal of US TV, to those of French-speaking residents of Quebec, who watch very little U.S. television.

The study found that, of the three drugs it covered, two showed no difference in prescription rates between the English- and French-speaking groups. The rates for Zelnorm, on the other hand, did jump 45% among the English-speaking group after ads for the drug were shown on TV, but the increase in activity did not last over time. The study seems to challenge the common perception among doctors and other healthcare experts that the ads create consumer demand for the advertised drugs. However, many caution that a study that covers only three drugs is too small to draw any solid conclusions.