A study of how DTC TV advertising impacted different populations in Canada suggested that ads may have little impact on consumers.
The study, by Harvard Medical School researchers, looked at the impact of three big TV campaigns—for Nasonex, Enbrel and Zelnorm—on English- and French-speaking Canadians, the idea being that those for whom French was the primary language would be largely insulated from ads appearing on English-language American TV. Campaigns for Nasonex and Enbrel didn't even move the needle in the number of filled prescriptions between the populations per capita, and Zelnorm ads prompted only a brief bump in usage among English speakers.
“Exposure to US [DTC] advertising transiently influenced both Canadian and US prescribing rates for tegaserod (Zelnorm), a drug later withdrawn owing to safety concerns,” the study concluded. “The impact of [DTC] advertising on drug use seems to be highly variable and probably depends on the characteristics of the advertised drug, the level of exposure to direct to consumer advertising and the cultural context.”
DTC advertising is banned in Canada, but Statistics Canada, they noted, “estimates that around 30% of TV watched by English-speaking Canadians is foreign sourced,” most of that from the US.
The study appeared Sept. 2 in the British Medical Journal.