The aggressively healthy American prescription drugs advertising market could be feeling the first symptoms of a chill.

Spending on selling prescription products directly to consumers has swollen in the last seven years to a massive $3.8 billion (€2.8bn, £1.9bn), since government watchdog, the Food and Drug Administration, lifted a longstanding ban on DTC ads.

However, worries over Merck's painkiller Vioxx and its recent high profile withdrawal from the market - after FDA approval and expensive marketing extolling its advantages over other medications - have prompted consumer doubts about information in drug commercials and ads.

As a result of these health concerns and the sheer volume of advertising in a hugely competitive arena, marketers have to come up with ways of ensuring consumers don't switch off. Fariba Zamaniyan, vp at market researcher Ipsos Health, says response levels to direct-to-consumer drug advertising have fallen and will continue to do so.

In February 2002, twenty-five percent of consumers surveyed said an ad had prompted them to discuss with their doctors the drug being advertised. The response rate dropped to 19% in February this year and remains on that plateau six months later.

Val DiFebo, managing partner of the Deutsch ad agency in New York, welcomes a proposal by the FDA to cut the verbiage in print ads for drugs "so people will actually read it".

She says: "You want to make it more digestible so they don't tune it out."

For example, she says the complete version of the so-called "fair balance" information, related to a drug's potential side effects, could be posted on a web site, while the print ads feature the salient points in larger type than presently.

Data sourced from New York Times; additional content by WARC staff