Phenylephrine: the flu drug that probably does nothing

As much as we might swear by a particular cure or treatment for an ailment, sometimes we’re simply deluding ourselves. At other times it’s the product manufacturers or marketers who are doing the deluding – either intentionally or otherwise. In the last decade or so, doubts have been raised about a key ingredient of many medications sold in Australia. That ingredient is phenylephrine, often referred to in marketing and on packaging as ‘PE’.

The apparent myth of phenylephrine has been exposed in research published by US scientists. Their research reveals the so-called ‘key’ ingredient of popular cold, flu and allergy treatments is nothing more than a placebo.

Yet if you head down to your local pharmacy today, you’ll have no trouble finding a host of phenylephrine-based medications. If phenylephrine doesn’t do any good, how can this be happening?

Unpacking the truth of phenylephrine

That’s a very good question, and one that doesn’t have a straightforward answer. There are several aspects to consider here. First, does phenylephrine do no good at all or some good? Second, does it do any harm? And third, how do Australian authorities and laws deal with the answers to those first two questions?

Before answering those questions, a step back in time to the period before phenylephrine’s rise in popularity is in order. Because that rise would likely never have occurred if not for the ‘fall’ of another ingredient, pseudoephedrine.

Most YourLifeChoices readers will remember pseudoephedrine as a very popular and freely available treatment for cold, flu and allergies. But it had one major drawback – it is a precursor in the synthesis of methamphetamine. That made it highly vulnerable to exploitation by illicit drug manufacturers, forcing a change in its availability status.

From 2006 in Australia, pseudoephedrine-based products were classified as ‘pharmacist only’ or ‘prescription only’ medicines, depending on their pseudoephedrine level.

That left a gap on pharmacy shelves, and phenylephrine products quickly filled the space.

But the fact that phenylephrine products were not subject to the same restrictions was perhaps a clue to their effectiveness. Or in this case, their lack of effectiveness. If a medication doesn’t need a prescription can it be much good?

The truth is that many non-regulated medications can do good. Paracetamol and ibuprofen, for example, have plenty of scientific evidence supporting their efficacy as painkillers.

What the evidence says

In the case of phenylephrine, though, not so much. As far back as 2006, one study found that phenylephrine “was not significantly different from a placebo”. And then last year, a report published in the Annals of Pharmacotherapy landed a much bigger blow.

The title was, ‘Why Is Oral Phenylephrine on the Market After Compelling Evidence of Its Ineffectiveness as a Decongestant?’ That pretty much tells the story.

Associate Professor Nicola Smith, head of pharmacology at the University of NSW, pulled no punches in her assessment of the drug. She said it had been an open secret for some time that oral phenylephrine was a cold and flu fraud.

However, both the scathing 2022 report and Prof. Smith refer to oral phenylephrine. If taken via a nasal spray and used as directed, phenylephrine has indeed been shown to be effective.

So why then is the oral version still freely available? It may not be in time. America’s Food and Drug Administration (FDA) is considering a ban. And Australia’s equivalent, the Therapeutic Goods Administration (TGA), keeps a close eye on FDA decisions. But for now, according to a TGA spokesperson, oral phenylephrine will not be removed from the market.

Doing good versus not doing harm

Professor Andrew McLachlan, head of school and dean of pharmacy at the University of Sydney, revealed why. He said many medicines on the market held TGA approval, which showed they were high quality and safe for consumption. Importantly though, that approval did not mean they worked, he said.

In a nutshell, that means that while phenylephrine may not do you any good, it isn’t doing you any harm.

If you’ve been taking PE products orally and they seem effective, by all means feel free to keep taking them. But be aware that the effect might be purely a placebo one.

Have you been using oral phenylephrine medications? Will you now reconsider their use? Let us know via the comments section below.

Also read: Do you have the ‘yo-yo flu’? Experts explain what it is and how to avoid it

Health disclaimer: This article contains general information about health issues and is not advice. For health advice, consult your medical practitioner.

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