Why Many Cold Medicines Don’t Work to Relieve Congestion Doctors

Citing the findings, doctors, pharmacists and groups including the American Academy of Allergy, Asthma and Immunology and the American College of Clinical Pharmacy have said the pills shouldn’t be sold.

“It’s not a safety concern so it’s not a priority of the FDA,” said Dr. Ferreri, who supports ending phenylephrine’s use in decongestants. 

Johnson and Johnon’s Sudafed PE also contains phenylephrine.

Haleon PLC, which makes versions of Theraflu that also contain phenylephrine, declined to comment. 

Phenylephrine is also the main ingredient in injections that increase blood pressure and in topical treatments to relieve hemorrhoids. As a decongestant, studies have found phenylephrine works when given via nasal spray. 

In 1976, the FDA included phenylephrine, along with two other main decongestant ingredients called phenylpropanolamine and pseudoephedrine, as over-the-counter products when it overhauled its regulations.

In 2000, the FDA asked manufacturers to remove phenylpropanolamine over concerns about an association with hemorrhagic stroke. Six years later, Congress restricted sales of products containing pseudoephedrine to behind the pharmacy counter because the ingredient can be used to make methamphetamine. 

Phenylephrine’s use in over-the-counter decongestants increased after use of the other two ingredients was restricted.  

Phenylephrine is now in more than 260 oral nose and sinus medicines, according to a 2020 paper published in JAMA Otolaryngology–Head & Neck Surgery. 

Like many older drugs, phenylephrine didn’t go through the rigorous clinical trials regulators require today for medications.

The Bayer AG company found phenylephrine was ineffective, according to published studies, and kept using pseudoephedrine in Claritin-D sold behind a pharmacy counter. 

Bayer AG now makes Claritin-D, after acquiring it from Merck.

Leslie Hendeles and Randy Hatton, professors at the University of Florida pharmacy school who reviewed research on phenylephrine drugs in the 2000s, said they found insufficient evidence supporting phenylephrine effectiveness. 

In 2007, they first petitioned the FDA to review whether a 10 milligram phenylephrine pill was effective. Experts advising the agency voted, later that year, that the dosage may be effective, but more study was needed.

Since then, researchers have published at least four randomly-controlled studies. All found that phenylephrine wasn’t more effective at relieving congestion than placebo. Schering and then Merck funded the studies. 

In one company-sponsored study, researchers found the 10 milligram doses as well as three stronger doses weren’t more effective than a placebo in a study of 539 people published in 2015 in the Journal of Allergy and Clinical Immunology. 

Physicians and pharmacists say because oral phenylephrine is metabolized in the gut and liver, it can’t reach the bloodstream in sufficient levels and cause the blood vessels to narrow and provide relief.

“The evidence is clear that oral phenylephrine does not work,” said Dr. Hatton. “If it doesn’t get into the blood in the first place, it can’t go to the nose and cause nasal constriction and therefore relieve your congestion.”

Garret FitzGerald, a professor of translational medicine and therapeutics at the Perelman School of Medicine at the University of Pennsylvania who served on the 2007 FDA advisory panel, reviewed the recent studies at the request of The Wall Street Journal, and said the studies and their findings seemed credible.