The Food, Drug and Cosmetic Act makes it illegal to sell a prescription drug for any purpose other than what’s listed on the label.

Nevertheless, a divided federal appeals court recently tossed out the conviction of a former drug sales rep who was recorded pitching a doctor on other uses of a medicine approved by regulators solely to treat the sleep disorder narcolepsy.

And here’s the kicker: The court ruled that the sales rep had a free-speech right to promote the drug’s unapproved uses.

I’m as big a fan of the First Amendment as anyone, but this decision strikes me as fundamentally flawed.

We’re not talking about a right to express yourself. We’re talking about selling stuff — stuff that could harm or even kill you if used improperly.

Moreover, it would seem that a serious blow has been dealt to the Food and Drug Administration’s power to ensure the safety of prescription meds. The drug industry can now pitch any use for its products, regardless of what regulators say.

“This is a complete disgrace,” says Steven Miles, a professor of medicine and bioethics at the University of Minnesota. “What this basically does is destroy drug regulation in the United States.”

Felicia Cohn, director of medical bioethics for Kaiser Permanente Orange County, was more circumspect. But only slightly so.

“This completely undermines the FDA’s authority over how drugs are marketed,” she says. “I can’t imagine that the marketing folks in the drug industry won’t seize upon this as an excuse to sell almost all drugs beyond their approved usage.”

The case before the U.S. 2nd Circuit Court of Appeals in Manhattan began in 2005 when Alfred Caronia, a former sales rep for Orphan Medical, later acquired by Jazz Pharmaceutical, was targeted in a federal investigation into questionable drug-industry sales practices.

He was recorded telling a doctor that the narcolepsy drug Xyrem could also be used to treat insomnia, fibromyalgia and other conditions, even though the FDA hadn’t approved such uses. Caronia was convicted by a jury in 2008.

In his appeal, Caronia argued that the First Amendment gave him the right to discuss so-called off-label drug uses, and the court agreed.

“The government clearly prosecuted Caronia for his words — for his speech,” the majority wrote in the 2-to-1 decision. It concluded that “the government cannot prosecute pharmaceutical manufacturers and their representatives” under the Food, Drug and Cosmetic Act for speech promoting off-label drug uses.

Judge Debra Ann Livingston, the sole dissenter on the panel, countered that by overturning Caronia’s conviction, “the majority calls into question the very foundations of our century-old system of drug regulation.”

The government is expected to challenge the ruling, either before the full appellate court or at the U.S. Supreme Court. The high court already has determined that unlimited political donations can be made in the name of free speech.

R. Alta Charo, a professor of law and bioethics at the University of Wisconsin, explained it to me like this:

Let’s say a drug company came up with a medicine that the FDA approved for controlling a patient’s blood pressure. But later on, the company discovered that the medicine has an interesting side effect: It grows hair.

A cure for baldness, obviously, has blockbuster potential. But under the old rules, the drug company would have had to go back to the FDA and receive approval for the blood-pressure medicine to be marketed as a hair restorer.

Now, it wouldn’t have to. It could claim a free-speech right to say whatever it wanted about the drug’s usage.

The drug Viagra was originally intended to lower blood pressure and treat angina. It was only during testing that its maker, Pfizer, noticed that Viagra had an unexpected effect on another aspect of the male anatomy.

So Pfizer asked the FDA for permission to market its heart drug as a remedy for erectile dysfunction. The federal agency, in turn, gave Pfizer’s research a good going-over before giving its nod.

“What we’re losing with this court decision is the safeguard of an independent arbiter,” Charo says. “It’s very problematic.”

Alexander Capron, a professor of law and medicine at the University of Southern California, calls the ruling “enormously significant” and says it eliminates an important hurdle that drugs have had to clear before reaching the market.

“The danger to consumers is that a drug will be marketed without having the relative balance between efficacy and safety adequately addressed,” he says.

Businesses and their conservative friends in Congress routinely argue that regulations get in the way of commerce and innovation and that the market should be left to work its magic.

The flip side of that pie-in-the-sky perspective is GlaxoSmithKline agreeing to pay $3 billion in July for promoting antidepressants and other drugs for unapproved uses. Or Johnson & Johnson agreeing in August to pay $181 million to settle cases over the questionable marketing of an antipsychotic drug.

FDA rules are there for a reason, and that reason is to protect public health.

Drug companies have everything to gain by being able to sidestep regulatory oversight. The rest of us gain nothing.

David Lazarus, consumer columnist and contributor to American Public Media’s Marketplace radio program. david.lazarus@latimes.com