The FDA’s 16-member advisory panel unanimously voted yesterday that oral phenylephrine, a common active ingredient in cold medications, is no better than a placebo for treating congestion. The call by the panel sets up potential FDA action that could force the removal of certain over-the-counter medications containing the ingredient — including certain formulations of Mucinex, Sudafed, Tylenol, and NyQuil — from store shelves.

As noted by The New York Times, the panel’s vote doesn’t necessarily mean the FDA will take action, but it usually follows panel recommendations. That said, the FDA may hold off for many months, pending contested findings by drug makers and other considerations.

The panel tossed out several older studies that showed the drug was effective over issues with data integrity, small sample sizes, methodological problems, and more.

Newer data from studies the panel says are more consistent with modern clinical trial standards showed phenylephrine simply “was not significantly different from placebo” in the recommended dosage, including trials from 2007 that the FDA had reviewed when considering the drug after a citizen petition prompted it to do so.

The panel cited the drug’s low bioavailability, a term referring to qualities that allow the drug to be absorbed by the human body, as the main reason the drug should be removed from the market. The drug could potentially work with increased dosage, but most of the FDA advisors thought that was unnecessary or even dangerous to consider for phenylephrine. In a video recording, the panel explained their unanimous vote:

Dr. William Figg from the National Cancer Institute said he believed that the drug’s “poor bioavailability … precludes any further studies of increasing the dose.” Expounding on that, Dr. Paul Pisarik said the drug has potentially negative effects at higher doses. “If we do 60 or 80mg of phenylephrine, then we have to start worrying about blood pressure increases since at 100mg, the blood pressure goes up by 10 points.”

Jennifer Schwartzott said the drug “should have been removed from the market a long time ago,” while Dr. Stephen Clement said that although the drug itself isn’t dangerous, its usage by patients should be considered unsafe because it potentially delays actual treatment of disease symptoms.

Members of the panel agreed that the presence of phenylephrine in a medication shouldn’t automatically rule out its usefulness since other ingredients can still treat cold symptoms. The panel cited pseudoephedrine as an effective alternative though while it’s technically available without a prescription, you must talk to a pharmacist to get it because, in large quantities, it can be used to make methamphetamines.