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Tylenol can kill, and McNeil, the Johnson & Johnson-owned company that distributes it, has done startlingly little to protect its consumers over the decades. That's basically the gist of a novella-length investigation into the drug and its most active ingredient, acetaminophen, published by ProPublica this morning. Despite decades of science demonstrating how frighteningly easy it is for consumers to overdose on the pain reliever—causing serious liver damage or death—McNeil remains stubbornly reluctant to implement the label warnings or dose limitations that have been called for since the 1970s. 

If you've got an hour or two to spare, the full investigation by Jeff Gerth and T.Christian Miller is well worth a read. But we've pulled out some of the most striking findings below.

About 150 Americans die every year from acetaminophen poisoning. 

In fact, that figure's actually a fairly conservative estimate. Over the summer, Time reported that closer to 500 people die in the U.S. from overdosing on acetaminophen, with another 55,000 to 80,000 ending up in the ER for the same reason. And it's not just Tylenol—the ingredient also appears in Excedrin pain tablets, Sudafed sinus pills, and hundreds of other over-the-counter products.

What makes acetaminophen especially dangerous, though, is the worryingly small gap between the recommended dose and the dose that can harm or even kill consumers. As one FDA report put it, that gap puts "a large fraction of users close to a toxic dose in the ordinary course of use."

You're more likely to die from acetaminophen poisoning if you overdose by accident than if you commit suicide.

This was one finding by a Dallas doctor named Will Lee, who spent decades studying acetaminophen toxicity. It sounds preposterous, but makes sense given how long it take for acetaminophen poisoning to kick in. 

Consider: those who attempt suicide often regret the decision almost instantly, so in this case they'd take McNeil's poison antidote, which is likely to work if taken within eight hours of the overdose. That's reassuring. But more worrisome is the fact that those who poison themselves by accident are not likely to take the antidote at all because they don't realize anything is wrong (and, in large part, because the dose that can hurt or kill is so close to the recommended dose). Hence, ProPublica reports, those patients symptoms "took several days to develop and resembled those of the flu, for which many of them had taken the drug in the first place."

The FDA still hasn't bothered to complete the acetaminophen investigation it began more than 30 years ago. 

The Food & Drug Administration launched its investigation into the drug's safety in the late 1970s, "as part of the agency’s larger mandate to assess the safety and efficacy of older medicines." It still hasn't wrapped it up (though in 2011 it acknowledged its unfortunate "inability to identify precise toxicity thresholds").

The excuse for this failure: "a combination of science and bureaucracy."

McNeil has fought bitterly against stronger warning labels.

Despite the obvious health risks Tylenol entails, McNeil has done all it can to fight proposals to include warning labels and dose restrictions. In one small victory, for instance, the FDA managed to place a label on prescription acetaminophen stating, "acetaminophen has been associated with cases of acute liver failure, at times resulting in liver transplant and death." But such a warning remains absent from the far more common over-the-counter Tylenol.

As one FDA official told ProPublica, the company is "more aggressive than most" when it comes to heeding "the competitive nature of the marketplace." That's perhaps an understatement.  

And the company's been sued about 100 times in the past few years.

Most of the lawsuits point to inadequate label warnings and claim injury or death after taking little more than the recommended daily dose of Tylenol. Even more disturbingly, one study found six consumers who had experienced major liver harm after taking less than the recommended dose. 

But none of this seems to have hurt Tylenol's sales. As ProPublica concludes, it remains the nation's "No. 1 over-the-counter adult pain medicine"—and there's little sign it'll be bumped any time soon.

Here's the full report.

This article is from the archive of our partner The Wire.