Decongestants should not be given to young children because there is no evidence they help clear up a blocked or runny nose and their safety is unclear, according to experts investigating the effectiveness of treatments for the common cold.
Overall, their analysis of research evidence, published in the British Medical Journal, suggests there is little proof most over the counter cold remedies actually work.
“Patients often take over the counter decongestants before they consult the GP”
Instead, they advise clinicians to tell patients there are no “magic bullets” when it comes to treating colds, which will generally clear up by themselves in a week to 10 days.
Professor Mieke van Driel, head of primary care and general practice at the University of Queenland’s faculty of medicine, and colleagues examined published evidence on cold treatments for children and adults.
They focused on nasal symptoms after asking a snapshot sample of people seeking cold remedies in a pharmacy what bothered them most.
For adults with “bothersome symptoms” such as congestion, a runny nose and sneezing, the evidence suggests using decongestants on their own, or with antihistamines or painkillers, for three to seven days at the most can have a small effect.
“They can cause adverse effects such as drowsiness or gastrointestinal upset”
However, the authors go on highlight “disturbing” side effects such as drowsiness as well as, sleeplessness, headache and stomach upset and warn using decongestants long-term can lead to chronic nasal congestion, which is hard to treat.
“Patients often take over the counter decongestants before they consult the GP and commonly for more than just a few days,” said the study paper. “They may not be aware that prolonged use can lead to chronic nasal congestion.”
While paracetamol and anti-inflammatory drugs are sometimes prescribed for pain relief, they do not appear to improve nasal congestion or a runny nose, the researchers found.
Meanwhile, other treatments such as steam inhalation, echinacea, vapour rub, eucalyptus oils and drinking more fluids were either not effective or had not been studied.
“None of the other commonly used over the counter treatments has been shown to relieve nasal symptoms and many have not been studied at all,” said the study authors in their paper.
“Based on the currently available evidence, reassurance that symptoms are self limiting is the best you can offer patients,” they said.
In particular, there was a lack of trial evidence when it came to treating children aged under 12, who are more likely to catch colds, enduring around six to eight per year on average.
“Reassurance that symptoms are self limiting is the best you can offer patients”
Decongestants or medicines containing antihistamine should not be given to children aged under six, conclude the researchers, who also advise caution for those aged six to 12 because the safety risks are “unclear”.
“There is no evidence that these treatments alleviate symptoms and they can cause adverse effects such as drowsiness or gastrointestinal upset,” said the paper.
“Serious harm, such as convulsions, rapid heart rate and death, has been linked to decongestant use in very young children,” it added.
Meanwhile, none of the other commonly used over the counter or home remedies, such as heated humidified air, eucalyptus oil or echinacea, are supported by adequate evidence.
Clinicians should “explain that a cold is distressing but should pass in seven to 10 days”, the researchers advised.
If parents are concerned about their child’s comfort “saline nasal irrigations or drops can be used safely but this may not give the desired relief,” they said in their report.
While further trials of treatments for the common cold – including Chinese and other herbal remedies and combinations of decongestants, painkillers and antihistamines – are under way, these are unlikely to provide clear evidence on nasal symptoms, the authors conclude.
However, one trial of guaifenesin, an expectorant used to treat coughs, “may add to the evidence base”.