It’s Cold Season, and Your Decongestant Doesn’t Work. Now What?

Phenylephrine is the most popular oral decongestant in the country, but further scrutiny by scientists has found that the ingredient is actually no better than a placebo.

Acting on results from at least five studies over the last 20 years – including a 2022 commentary by two University of Florida pharmacists, who plainly stated that oral phenylephrine is ineffective as a decongestant – a Food and Drug Administration (FDA) advisory panel last week unanimously concluded the ingredient doesn’t work in oral form.

Phenylephrine is used in many over-the-counter cold and allergy oral medications, including some DayQuil, Sudafed PE, and Benadryl products. It remains to be seen what action the FDA may take, but possibilities include not allowing oral medications with phenylephrine to be sold, or giving manufacturers a grace period to substitute other ingredients.

According to reports, the oral decongestant industry, which bankrolls a deluge of cold-relief advertisements every fall and winter, generates roughly $1.8 billion in sales annually.

Phenylephrine nasal spray remains effective at relieving congestion, said Sunny Linnebur, PharmD, a professor in the Department of Clinical Pharmacy at the Skaggs School of Pharmacy and Pharmaceutical Sciences.

“One of the problems with the oral phenylephrine is it’s not bioavailable,” Linnebur said. “It’s absorbed and then degraded really quickly, so the concentrations are likely not high enough in the nose to really help provide benefit. But if you used nasal phenylephrine, it gets right to the source.”

In the following Q&A, Linnebur explains how oral phenylephrine got flagged as ineffective and what could happen next. The interview has been edited for brevity and clarity.

Phenylephrine was approved for use as an oral decongestant ingredient several decades ago, but now has been deemed basically no better than a placebo. How did this situation come to pass?

Well, part of the reason that happened was that the safety and effectiveness data that were submitted years ago were low-quality studies. The studies were conflicting, and the FDA may have been more lenient in terms of the ingredient itself. It was difficult to know how effective it was.

So, it wasn’t until a couple pharmacists a few years back raised the question again to the FDA and asked them to review it that it got a little more attention. And because phenylephrine is a product that is lucrative to market over the counter, no one was asking to have it removed other than these couple pharmacists. Also, when pseudoephedrine went behind the counter (in 2006, as a measure to rein in its misuse as an ingredient to make methamphetamine), oral phenylephrine gained in popularity and became the only other oral decongestant that was available outside the pharmacy.

Could you expand on the quality of the studies a bit? Were there problems with the integrity of the data, or findings of inconsistent data?

Some of these studies go back to the 1970s, or even earlier, in the ’60s. Some of the studies were single-dose studies, so effects of the drug over a normal treatment course – several days – were not evaluated. There were inconsistencies among side effects and benefits at different doses. Some studies showed benefits to patients and other studies did not. Similarly, some studies showed side effects and others did not. There may have also been quality control issues.

Now we have higher quality, more consistent studies, with better measurements of nasal congestion.

What is the process now? Does the FDA look at this and rule that phenylephrine needs to be immediately removed from store shelves, or does it offer a grace period to the drug manufacturers?

I think the FDA would take quick action and require a recall if there was a safety concern, but there’s no safety concern. If the FDA agrees with the advisory panel and decides oral phenylephrine is not effective, before products are removed, there will be a time for public comment.

Given that the FDA’s advisory panel vote was unanimous, though, I think the FDA may weigh in and decide to remove phenylephrine from the list of OTC medications they consider generally safe and effective. Eventually, this would mean products will be removed from the shelves at pharmacies, but also from gas stations, grocery stores, vending machines and hotel gift shops. This could be a much bigger recall than your standard over-the-counter medication.

Will the findings on oral phenylephrine spur pseudoephedrine, which has been shown to be an effective oral decongestant, to be more available? In other words, to shift it back to an over-the-counter medication rather than a behind-the-counter product?

I don’t think so. There is still concern of methamphetamine abuse in the United States, and moving pseudoephedrine behind-the-counter was pretty effective at reducing the availability of pseudoephedrine for this purpose.

Pseudoephedrine is an effective oral decongestant, but so are the nasal decongestant products, which are more easily obtained by patients over-the-counter. Oxymetazoline, phenylephrine, and naphazoline nasal sprays are effective, and are often safer than oral decongestants. They do not cause insomnia or raise blood pressure, they are safe to use during pregnancy and for women who are breastfeeding, and they are safe for men with an enlarged prostate.

In a physiological sense, what do these ingredients do to the body?

Decongestants vasoconstrict the blood vessels in the nose, helping to reduce the swelling caused by cold viruses and allergies. But this also means that the oral decongestants do it all over the body. This is how pseudoephedrine could potentially increase blood pressure a little bit, because it’s affecting the blood vessels all over the body, in addition to the nose. But the nasal decongestants act a little quicker than the oral decongestants at doing the same thing and do not affect the rest of the body.

If the FDA rules that phenylephrine needs to be removed from oral cold and allergy medications, would you view this as a disruptor to the common cold remedy market in terms of its ripple effect?

Yes, it probably would be a disruptor, but I wouldn’t have a problem with that. I don’t think many pharmacists recommend it because they all know that phenylephrine is not as effective as oral pseudoephedrine, and they know there are nasal decongestants that are available as well. Production of these alternative agents may need to increase for the extra demand.

The bottom line, though, is that phenylephrine products treat nasal congestion from a cold or allergies. Given that these illnesses are not immediately harmful and are often self-limiting, patients don’t necessarily need a drug therapy for their nasal congestion symptoms. But if they want a treatment, there are multiple other safe and effective options to treat nasal congestion.