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ScienceMay 6, 2017

Cold discomfort pharma: what does the science say on whether the drugs work?

Drugs Tablets Pain Medication Pills Headache

Over-the-counter cold-and-flu remedies are mostly useless, says Consumer NZ. The industry strongly disagrees. Siouxsie Wiles takes a look at the studies.

Over the last few days a fight has broken out between Consumer NZ and the New Zealand Self Medication Industry over expensive cold and flu products. Consumer NZ says the products are no more effective than taking paracetamol, which can be bought for a fraction of the price. The MSI strongly disagrees and says consumers can continue to use over-the-counter cold medicines with confidence. Whom should we believe?

An artists impression of Siouxsie with the lurgy. Photo: Westend61/Getty

Last year I had one of the worst colds I’ve had in a long time. Some pesky rhinovirus had turned my nose into a virus-producing factory, and I felt so bunged up with mucus I could hardly breathe. Cue a trip to the pharmacy to buy one of the many cold and flu products which claim to provide fast and effective relief from blocked and runny noses. As well as paracetamol, they contain phenylephrine hydrochloride, included to act as a nasal decongestant.

Two hours later, and with none of the promised relief in sight, I jumped on to the internet to find out if it was safe to up the dose a little. As a research scientist, it wasn’t Google I searched, but PubMed, a search engine maintained by the US National Library of Medicine. This fantastic free resource allows anyone to access the abstracts of millions of studies published in scientific and medical journals. I found abstracts with catchy titles like “Oral phenylephrine HCl for nasal congestion in seasonal allergic rhinitis: a randomized, open-label, placebo-controlled study” and “A placebo-controlled study of the nasal decongestant effect of phenylephrine and pseudoephedrine in the Vienna Challenge Chamber”. In other words, studies that looked at how effective phenylephrine is as a nasal decongestant. And they weren’t just asking people if they felt less congested. They were measuring stuff like “peak nasal inspiratory flow” and “nasal airway resistance”. Excellent, I thought. Hopefully they would have some information on different doses too.

Turns out the studies are clear: phenylephrine doesn’t do diddly-squat for nasal decongestion. Nada. Zilch. Even at doses four times higher than in the products we can buy in our pharmacies. Bugger. So how can it be included in those products? Turns out phenylephrine was approved by the US Food and Drug Administration (FDA) as a nasal decongestant back in the 1970s, apparently on the basis of inhouse studies by the pharmaceutical companies involved. It became more widely used in cold and flu products when pseudoephedrine, which really does work as a nasal decongestant, was restricted because it can be used to make the illegal drug methamphetamine (also known as P).

Presumably, when the companies had to replace pseudoephedrine in their products, it was easy to swap it out for something that sounded similar. It’s a pity phenylephrine doesn’t actually have the same effect on blocked noses. But it’s approved by the FDA, which seems to be all that the New Zealand Self Medication Industry needs to justify charging heaps more for what is effectively paracetamol. That’s certainly what it sounded like when Susie Ferguson challenged their executive director Scott Milne on Morning Report.

What’s depressing is that all of this was brought up a decade ago, when the change first happened and pseudoephedrine was restricted. How much money have people wasted since then? What’s even more depressing is that phenylephrine isn’t just some benign pseudo-pseudoephedrine. It’s a drug with its own potential side effects, which include slowing people’s heart rate. It could even be harmful for some people, especially if they are taking other medications.

The studies are definitely on Consumer NZ’s side, so you’d be best following their advice the next time you have a cold: take some paracetamol and put your feet up for a few days. The paracetamol won’t do anything for your stuffy nose, but it will relieve some of your other symptoms, and staying at home and resting will stop you spreading your cold around.


Day JH, Briscoe MP, Ratz JD, Danzig M, Yao R (2009). Efficacy of loratadine-montelukast on nasal congestion in patients with seasonal allergic rhinitis in an environmental exposure unit. Ann Allergy Asthma Immunol. 102(4):328-38. doi: 10.1016/S1081-1206(10)60339-0. [Link:]

Hatton RC, Winterstein AG, McKelvey RP, Shuster J, Hendeles L (2007). Efficacy and safety of oral phenylephrine: systematic review and meta-analysis. Ann Pharmacother. 41(3):381-90. [Link:]

Horak F, Zieglmayer P, Zieglmayer R, Lemell P, Yao R, Staudinger H, Danzig M (2009). A placebo-controlled study of the nasal decongestant effect of phenylephrine and pseudoephedrine in the Vienna Challenge Chamber. Ann Allergy Asthma Immunol. 102(2):116-20. doi: 10.1016/S1081-1206(10)60240-2. [Link:]

Meltzer EO, Ratner PH, McGraw T (2015). Oral phenylephrine HCl for nasal congestion in seasonal allergic rhinitis: a randomized, open-label, placebo-controlled study. J Allergy Clin Immunol Pract. 3(5):702-8. doi: 10.1016/j.jaip.2015.05.007. [Link:]

Meltzer EO, Ratner PH, McGraw T (2016). Phenylephrine hydrochloride modified-release tablets for nasal congestion: a randomized, placebo-controlled trial in allergic rhinitis patients. Ann Allergy Asthma Immunol. 116(1):66-71. doi: 10.1016/j.anai.2015.10.022. [Link:]

The Spinoff’s science content is made possible thanks to the support of The MacDiarmid Institute for Advanced Materials and Nanotechnology, a national institute devoted to scientific research.

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