WASHINGTON — Those ever-present TV drug ads showing patients hiking, biking or enjoying a day at the beach could soon have a different look: New rules require drugmakers to be clearer and more direct when explaining their medications’ risks and side effects.

The U.S. Food and Drug Administration spent more than 15 years crafting the guidelines, which are designed to do away with industry practices that downplay or distract viewers from risk information.

Many companies have already adopted the rules, which become binding Wednesday. But while regulators were drafting them, a new trend emerged: thousands of pharma influencers pushing drugs online with little oversight.

A new bill in Congress would compel the FDA to more aggressively police such promotions on social media platforms.

“Some people become very attached to social media influencers and ascribe to them credibility that, in some cases, they don’t deserve,” said Tony Cox, professor emeritus of marketing at Indiana University.

Still, TV remains the industry’s primary advertising format, with over $4 billion spent in the past year, led by blockbuster drugs like weight-loss treatment Wegovy, according to ispot.tv, which tracks ads.

The new rules for TV and radio ads instruct drugmakers to use simple, consumer-friendly language when describing their drugs, without medical jargon, distracting visuals or audio effects. A 2007 law directed the FDA to ensure that drug risk information appears “in a clear, conspicuous and neutral manner.”

The FDA has always required that ads give a balanced picture of the benefits and risks, a requirement that gave rise to those long, rapid-fire lists of side effects parodied on shows like “Saturday Night Live.”

But in the early 2000s, researchers began showing how companies could manipulate images and audio to de-emphasize safety information.

In one example, a Duke University professor found that ads for the allergy drug Nasonex, which featured a buzzing bee voiced by Antonio Banderas, distracted viewers from listening to side effect information, making it harder to remember.

Such overt tactics have largely disappeared from drug ads.

“In general, I would say the ads have gotten more complete and transparent,” says Ruth Day, director of the medical cognition lab at Duke University and author of the Nasonex study.

The new rules are “significant steps forward,” Day said, but certain requirements could also open the door to new ways of downplaying risks.

One requirement instructs companies to show on-screen text about side effects while the audio information plays.

A 2011 FDA study found that combining text with audio increased recall and understanding.

But the agency leaves it to companies to decide whether to display a few keywords or a full transcript.

Viewers tend to tune out long lists of warnings and other information. But experts who work with drug companies don’t expect those lists to disappear. While the guidelines describe how the information should be presented, companies still decide the content.