YouTube Drug makers are legally required to spend money telling you their products might lead to a series of horrifying side effects, up to and including death.

Needless to say, for the pharmaceutical industry, this presents a communications challenge.

But nearly two decades after television ads for prescription drugs began flooding American homes, drug makers have also perfected their delivery — allowing them to include the information they are obligated to provide while minimizing how scary it might sound.

And in interviews, the actors paid to deliver these warnings — bit players in the $5 billion-a-year industry of prescription drug advertising — say there's an art to it.

"We use the same approach medical professionals do, telling a patient calmly: 'We're going to perform this surgery and there's a 60 percent chance you won't live,'" said Joey Schaljo, who has worked as a voiceover actor on drug ads and who has a knack for narrating endless lists of side effects.

How drug ad narrators obscure the risks

The United States is one of just two countries to allow direct-to-consumer ads on TV, and they've exploded in numbers since the Food and Drug Administration began allowing drug makers to claim their products could ease specific symptoms for specific conditions.

The FDA does insist, however, that the ads rattle off a long, usually grim, list of potential side effects. But how to do it without turning off customers?

Some ads use one narrator to talk about the benefits of the drug and a different actor to recite the risks — in a less engaging voice. Or the warning section may be written with more complex sentence structures, to make it harder for viewers to absorb.

"There's a shift in how the voice is used to make it easier to understand the benefits and less easy to understand the risks," said Ruth Day, a cognitive scientist at Duke University who has studied drug ads for more than a decade.

In one experiment, Day showed people commercials for two drugs that had similar side effects and addressed the same health condition. One of the ads rushed through the risks, while the other didn't. People who watched the ad with the hurried narration had a much harder time remembering the drug's side effects.

Another common trick: Keep the voice actor who talks about risks offscreen.

Research has found that consumers absorb the most information when they can see people speaking rather than just hearing them. But "sometimes all the positives are said by someone you can see and all the negative things and risks are said by voiceover," Day said.

Drug makers can't get too clever, however, or they risk sparking anger at the FDA.

But it's a delicate balance

flickr/nateone Back in 2008, the FDA sent a warning letter to Bayer, complaining that two ads for the birth control pill Yaz seemed designed to distract viewers from the list of potential side effects. As a narrator ran through the list, the ad featured a kaleidoscope of "fast-paced visuals," including women singing and chatting with friends, the FDA said.

"These complex presentations distract from and make it difficult for viewers to process and comprehend the important risks being conveyed," the FDA wrote. "This is particularly troubling as some of the risks being conveyed are serious, even life-threatening."

Bayer was required to run corrective ads with more emphasis on the side effects.

Ever since, most drug companies have been careful not to distract views from focusing on the mandatory list of risks, said Adrienne Faerber, a health policy researcher at the Dartmouth Institute who has studied how well people understand drug ads.

In fact, she now often sees ads where that section seems deliberately dull, set to "slow, swelling string music," and with a languid, understated narration, she said. "It lulls you into a very calm state," Faerber said. But that's not necessarily going to make consumers absorb the message better than they would with a warp-speed narration.

And the FDA can't do much about ads that bore consumers into ignoring the side effect lists: "There's no requirement for [drug manufacturers] to present things in a way that's cognitively engaging," Faerber said.

Voice actors called upon to read the warnings know they've got to strike a delicate balance.

"The challenge is saying all these really scary things, but in a way that people aren't frightened," said Debbie Irwin, a New York-based voice actor who also does medical narration. Irwin has done voiceover work for hospitals, medical technology companies, and drugs like Surfaxin, a treatment for a respiratory condition.

The tone Irwin tries to take? "Warm but factual," she said. "Absolutely I'm gonna sound like I know what the hell I'm talking about."

Schaljo said she often tries to sound like an in-the-know nurse. "You want the people to be able to absorb what you're saying," she said.

Striking the right tone isn't the only challenge for voice actors. Just think about making your living by rattling off phrases like "sphenopalatine ganglioneuralgia" or "vascular ischemia caused by thrombosis."

"You have to look up words a lot," Irwin said.