Phenylephrine vs. Pseudoephedrine: What is the difference between the two decongestants?

Phenylephrine vs. Pseudoephedrine: What is the difference between the two decongestants?

The key ingredient in many popular over-the-counter decongestants, including Sudafed PE and some NyQuil products, is ineffective, an FDA panel recently concluded. The drug, known as phenylephrine, was once a go-to treatment for sinus pressure and congestion. after the availability of another nasal decongestant called pseudoephedrine was restricted. The ineffectiveness of phenylephrine applies only to the drug in oral form, not in the form of a nasal spray.

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Phenylephrine — the main ingredient in many over-the-counter decongestants — doesn't work, a Food and Drug Administration (FDA) advisory panel concluded earlier this month.

The committee found that oral medications containing the ingredient are ineffective, but the decision did not apply to nasal sprays containing the active ingredient.

More than 240 FDA-approved products contain phenylephrine, which together brought in nearly $1.8 billion last year, the committee said in a statement. Some of the most popular medications include Sudafed PE, some Nyquil products, and Advil Congestion.

You may still find oral phenylephrine on drugstore shelves—the advisory committee's decision is not binding and the FDA is still reviewing the evidence. However, CVS Health will remove a "small number" of the ineffective oral decongestants - only those with phenylephrine as the sole active ingredient - from shelves, the company announced last week.

But in the meantime, here's what you need to know about how phenylephrine became the drug of choice, what went into the committee's decision, and whether it's OK to turn to a different but similar-sounding decongestant — pseudoephedrine — for a cold.

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What are phenylephrine and pseudoephedrine?

Phenylephrine is a medication used to relieve nasal discomfort and sinus congestion or pressure. This makes it part of a class of medicines called nasal decongestants.

Medications containing phenylephrine come in liquid or tablet form; A phenylephrine nasal spray is also available. The medication works by reducing the swelling of the blood vessels in the nasal passages to make it easier to breathe through the nose when you have a cold or allergies.

Pseudoephedrine is also a nasal decongestant and works in the same way as phenylephrine: by relieving sinus congestion and pressure due to colds or allergies.

The main differences between phenylephrine and pseudoephedrine are their effectiveness, side effects, and potential for abuse.

Medications containing phenylephrine were a response to the abuse of pseudoephedrine, which can be used to make methamphetamine, a synthetic stimulant. When Congress passed the Combat Methamphetamine Epidemic Act in 2005, pseudoephedrine remained over the counter but was placed behind the pharmacy counter to limit access.

“There was a need to find another option that could be available over the counter without the patient having the additional hassle of purchasing it at the pharmacy and having it monitored over time,” says Sterling Elliott, PharmD, a clinical pharmacist and assistant professor of orthopedic surgery at Northwestern University Feinberg School of MedicineHealth.

That option was phenylephrine — but it wasn't long before researchers questioned the drug's effectiveness.

Effectiveness of phenylephrine

In a 2007 paper, a team of researchers reviewed eight unpublished studies and found that phenylephrine did not appear to work better as a decongestant than a placebo.

The study prompted the FDA to review the drug's effectiveness. However, through various research, it was ultimately found that phenylephrine can clear congestion.

“The studies at the time were not well designed and had methodological problems and would not be accepted today,” said Leslie Hendeles, PharmD, author of the 2007 study and professor emeritus at the University of Florida College of PharmacyHealth. “The committee did not recognize the problems at the time.”

In a 2015 paper, researchers called on the FDA to reevaluate phenylephrine — and it ultimately did.

In its final statement released this month, the FDA advisory committee said it reviewed five studies conducted over the last decade and unanimously concluded that oral phenylephrine had no effect on congestion.

"The oral form may simply not be absorbed well enough, and the concentration in the blood vessels in and around the sinuses is not high enough to relieve the congestion," said Dr. Elliot. “This has been a concern for us for a long time.”

In a statement, the FDA said it is reviewing the evidence and has not yet decided on the status of oral phenylephrine. If the FDA revokes the drug's over-the-counter label as GRAS/E (generally recognized as safe and effective), stores may have to withdraw the drugs.

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What about pseudoephedrine?

The FDA committee's opinion comes as cold and flu season begins in the United States, leaving people unsure about their options when purchasing decongestants.

But there's good news: Pseudoephedrine works in the same way as phenylephrine — by reducing the swelling of blood vessels in the nasal passages — and there's evidence that it's effective when taken orally, Elliot said.

“For pharmacists and physicians, pseudoephedrine is really the first choice,” he said. “But of course this also involves additional regulations that arose out of concerns about misuse.”

Brand names that contain pseudoephedrine include Sudafed and Dimetapp Elixir, and it is widely available as a generic. Although you don't need a prescription for these medications, you can't buy them in bulk.

"It's a good idea to pre-purchase the pseudoephedrine products you think your family will need," said Janet Engle, PharmD, PhD, executive director of the Accreditation Council for Pharmacy Education (ACPE).Health.“Having these items on hand will save you a late-night trip to the pharmacy.”

"Although pseudoephedrine is an excellent decongestant, it is not suitable for everyone and every type of congestion," Engle said.

For example, a constipation caused by mucus buildup may require an expectorant to break it up, he said.

"Decongestant nasal sprays are also very effective in treating congestion, but are not a good choice for congestion that lasts longer than a few days," Engle added.

Using sprays for too long or too often can cause the spray to stop working, a phenomenon called rebound jam.

Hendeles said the most effective medication for allergic congestion is usually a nasal steroid like Flonase. “For both colds and allergies, nasal sprays are the most effective medications,” he added.

If you're not sure which product is best for you, Dr. Elliot to ask a doctor or pharmacist. "You can get a picture of what's really causing the congestion," he said, "and choose the right medications to treat it."