The Food and Drug Administration on Wednesday finalized a plan that would ask drug companies to voluntarily limit the use of certain antibiotics in animal feed, citing long-held concerns that their overuse in livestock promotes the development of drug-resistant bacteria that can infect people.

Many antibiotics that are widely used to treat human illnesses, such as penicillin, are mixed with animal feed in part to promote rapid growth and weight gain in farm animals. The prevalence of antibiotics in livestock has been linked in several studies to the creation of drug-resistant “superbugs” that can spread to humans who eat, or even work with, the animals.

The FDA is asking drugmakers to stop using 200 products for growth promotion and instead to use them solely to treat and prevent diseases. Companies that opt to do so will be required to revise their product labels to reflect the change. A separate agency proposal would give the companies three months to detail their strategies and three years to adopt them.

Once the drugs are relabeled, those antibiotics would no longer be available to farmers over the counter, as they are now. A veterinarian would have to prescribe them.

The plan attempts to address a decades-long debate about a widely recognized public health hazard with global implications. As scientific evidence has mounted about the dangers of antibiotic resistance, the government has come under pressure to act swiftly. The voluntary path to regulation, supported by many in the drug industry, emerged as an efficient route to coping with the concerns, federal regulators said Wednesday.

While some public-health advocates hailed the move as a step in the right direction, others were less enthusiastic.

Some critics argue that the government must place an outright ban on the use of antibiotics for growth promotion, as it proposed doing decades ago, given the industry’s track record.

In 1977, the FDA proposed banning the use of penicillin and two forms of tetracycline for growth promotion. But after massive resistance from the industry and Congress, the agency never held hearings or took further action. The Natural Resources Defense Council and four other health and consumer advocacy groups sued the government last year to prompt action.

Last month, a federal district court in Manhattan ruled in favor of the plaintiffs and ordered the FDA to follow through on its initial proposal and start the proceedings that could lead to withdrawal of the drugs.

“The scientific evidence of the risks to human health from the widespread use of antibiotics in livestock has grown, and there is no evidence that the FDA has changed its position that such uses are not shown to be safe,” Judge Theodore H. Katz wrote.

The FDA must now grant the drugmakers an opportunity to appear at a hearing and prove that the antibiotics are safe, the court said. “If, at the hearing, the drug sponsors fail to show that the use of the drugs is safe, the [FDA] Commissioner must issue a withdrawal order,” Katz wrote.

The government is considering whether to appeal that decision.

FDA officials said that with so many products approved for growth promotion, it would take decades of administrative proceedings and possibly litigation to withdraw each drug.

They cite the agency’s effort to revoke approval of Baytril, an antibiotic used to treat chickens. The government succeeded in banning that use in 2004, but only after five years of efforts.

“This is the most expeditious way to get to the same result,” Michael Taylor, the FDA’s deputy commissioner for foods, said of the government’s plan, which was first proposed two years ago. “There is a real buy-in from the drug companies. They realize the time has come to make this shift.”

Jeff Simmons, president of the drugmaker Elanco, said he supports the approach. He said his Indiana-based firm already plans to veer away from some of its antibiotics and adopt more natural alternatives. To that end, the company announced this year that it had acquired Gaithersburg-based ChemGen, which produces an enzyme that unlocks nutrients that are not readily available in feed.

The industry is now turning its attention to the details of how this plan will be put in place, devoting particular attention to the role veterinarians will play.

Under the voluntary program, veterinarians will ultimately determine whether farmers get access to the antibiotics they’re seeking. The National Pork Producers Council said the plan “could be problematic, particularly for smaller producers or producers in remote areas who may not have regular access to veterinary services.”

The group also said the plan could increase the cost of food.

The agency is seeking comment on ways to modernize veterinary oversight. The Animal Health Institute, which represents companies that produce veterinary medicines, said it supports the new FDA program. But “there are details that must be addressed to make this approach practical and workable,” the group said in a statement.