A study published Tuesday in the online British Medical Journal revealed that DTC drug marketing campaigns have very little effect on sales, although since 2005, pharmaceutical companies have been spending a lot of money to advertise directly to patients.

The study was conducted by a group of researchers in Canada, where direct-to-consumer advertising of drugs is illegal. The only two countries that allow DTC drug ads are the United States and New Zealand. Nevertheless, Canadians are often exposed to American media so, using French-speaking Quebec as a control group, the researchers comparatively monitored for five years the prescription rates in English-speaking Canadian provinces and Quebec.

They performed the study on three different drugs: Enbrel (for rheumatoid arthritis), Nasonex (for nasal allergies) and Zelnorm (for irritable bowel syndrome), tracking prescription statistics according to data delivered by IMS Health Canada, a health information company that receives data from approximately 2,700 Canadian pharmacies.

Results showed that DTC advertising did not affect in any way the sales for the former two drugs, while the latter’s sales went up by 40% when the campaign began, but the spike did not last very long.

Therefore, it seems that the concerns about consumers starting to ask for drugs they see advertised in print and on TV, to which the Food and Drug Administration’s decision to ease its regulations-in 1997-gave rise, are bound to disappear.