Blame meth Luke Sharrett/Bloomberg via Getty

Cold medicine doing little to relieve your bunged up nose? That could be because a crack-down on chemicals that can be used to make crystal meth has meant some high-street cold medicines may be no better than placebo for relieving congestion.

Nine years ago, you could have walked into a shop on the UK high street and bought a packet of cold medicine that contained the decongestant pseudoephedrine. This drug has been used for decades, and works well, but in 2008 it was placed under tight controls when it became apparent that pseudoephedrine was being used for the illegal production of methamphetamine. Similar laws were introduced in the US in 2005.

Since then, pseudoephedrine has broadly been banished from shop shelves in the UK, the US and elsewhere. Today, you can only get products containing this compound either by obtaining a prescription, or asking a pharmacist for a packet from behind the counter. Pharmacists are now legally obliged to look for suspicious purchases, and to limit the number of tablets sold.


Ineffective alternative

Drug companies have responded to the regulations by replacing the compound with phenylephrine, which has long been known to be far less effective. Confusingly, popular cold remedy Sudafed – which takes its name from pseudoephedrine – now comes in two forms: a shop version, containing phenylephrine, and a behind-the-counter pseudoephedrine version.

But pharmacists are now calling for phenylephrine to be banned after research has shown that popping a pill or taking a spoonful of the stuff is ineffective for relieving nasal decongestion.

“The evidence is irrefutable – phenylephrine is no more effective than placebo” says Leslie Hendeles at the University of Florida.

In fact, there may never have been strong evidence that phenylephrine works. In 2006, cold expert Ronald Eccles at Cardiff University, UK, conducted a review of phenylephrine research and reported that he could not find any evidence that the drug works as a decongestant when taken orally – although it does seem to work as a nasal spray.

Less meth?

So we may all have blocked noses, but has the ingredient swap had any impact on crystal meth? Data from the US Drug Enforcement Administration suggests there was a decline in “meth lab incidents” after the Combat Methamphetamine Epidemic Act of 2005, which restricted access to pseudoephedrine. However, this decline was only short lived and may have been due to other factors such as increased training and awareness of the problem among law enforcement officers.

In the UK we don’t have a crystal meth problem on anywhere near the scale of the US. Only 240 people sought help for methamphetamine problems in the UK last year so it’s hard to tell what the effect of the intervention has been.

In the meantime, there may have been millions of people with perfectly treatable blocked noses, unknowingly taking what may well be little more than a placebo.