Blog | Friday, August 2, 2013

QD: News Every Day--TV ads may influence an antihistamine's efficacy


There's the placebo effect and the nocebo effect, and now there's an 'ad'cebo effect. Exposure to television ads for a brand of antihistamine increased the drug's efficacy, a study found.

Researchers conducted a randomized, controlled trial that objectively measured the physiological effect of ads for Claritin or Zyrtec on the efficacy of Claritin.

Researchers administered skin allergy tests for common allergens and took baseline measurements of the patients' wheal reactions. Subjects were asked about their beliefs in the efficacy of Claritin, given an open-label dose of 10 mg of the antihistamine, and then shown a movie along with ad breaks for either Claritin or Zyrtec. The Zyrtec ad stated that Zyrtec "starts working two hours faster than Claritin." The histamine challenges and wheal measurements were repeated at 60 and 120 minutes into the movie.

Results appeared online at the Proceedings of the Natural Academy of Sciences.

Among those without allergies, the efficacy at 60 min between the Zyrtec ad group and the Claritin ad group was not statistically significant. At 120 min, however, the efficacy of Claritin among Zyrtec ad watchers resulted in a 25% decrease in the size of the wheal reaction compared to baseline, and a 30.97% in the size of the wheal among Claritin ad watchers (difference, 5.97 percentage points; one-sided t test, P=0.043).

Researchers wrote that television ads can impact the physiological efficacy of a branded drug.

They wrote, "Our results suggest that a commercial phenomenon, television advertising, may be an important trigger for psychologically mediated physiological effects of a drug. Our findings also inform economic theories of advertising. They suggest that, at least in the context of new consumers of pharmaceutical products, advertisements can have a large impact on the efficacy of a drug."