That mumbling you heard on Friday wasn't from Ben Bernanke worrying about hyperinflation. It was from GlaxoSmithKline (NYSE:GSK), AstraZeneca (NYSE:AZN), Novartis (NYSE:NVS), and Schering-Plough (NYSE:SGP). They all sell asthma drugs that the Food and Drug Administration thinks might do more harm than good.

While the drugs work, there appears to be an increase in the number of asthma-related events -- deaths or the need for a patient to be intubated or hospitalized -- especially when they're used without a steroid.

The agency released documents for an advisory panel meeting on Wednesday and Thursday, and things aren't looking good for the drugs, called long acting beta-agonists (LABAs): Glaxo's Serevent and Advair, Novartis' and Schering's Foradil, and AstraZeneca's Symbicort. The drugs already have strong black-box warnings on them, but the FDA is considering eliminating their approval for use in children.

There's also the possibility of removing Serevent and Foradil from the market altogether. Those two drugs only contain LABAs, while Advair and Symbicort have a steroid added to the mix. Glaxo argues that pulling the LABA-only drugs is unnecessary because they're already co-prescribed with a steroid.

This is big business for Glaxo. Advair is its top-selling drug, with sales of more than $5.6 billion so far this year. Fortunately, most of the sales are to adults and nearly half occur outside the U.S., which wouldn't be directly affected by any FDA changes. As long as the FDA doesn't go crazy with its safety-consciousness, Glaxo should come out OK.

Still, investors should keep an eye on the results of the advisory panel meeting. The different divisions of the FDA appear a little at odds with one another, and the panel of experts could determine how far to the extreme the FDA wants to take this safety issue.

More Foolishness:

GlaxoSmithKline is a Motley Fool Income Investor pick.

Fool contributor Brian Orelli, Ph.D., doesn't own shares of any company mentioned in this article. The Fool's disclosure policy keeps you safe.