Children under six years of age should not be given decongestants to treat common cold symptoms such as nasal congestion or runny nose, because their safety is unclear, experts have warned.
 

Professor Mieke van Driel and colleagues from the University of Queensland noted that decongestants or medicines containing antihistamine have no evidence that they alleviate symptoms and should be given with caution to children under 12 years. "There is no evidence that these treatments alleviate nasal symptoms and they can cause adverse effects such as drowsiness or gastrointestinal (stomach) upset," van Driel said.

In children under 2 they have been associated with convulsions, rapid heart rate and death, she added. The common cold is usually caused by viruses and is mostly self limiting (symptoms clear in 7 to 10 days) but it can have a substantial impact on work, school, use of health services, and money spent on medications. 

For adults, the evidence suggests that using decongestants alone, or with antihistamines or analgesics, for a maximum of 3 to 7 days can have a small effect on nasal symptoms. However, side effects can include an increased risk of insomnia, drowsiness, headache, or stomach upset. Long-term use of decongestants can lead to chronic nasal congestion, which is difficult to treat, van Driel said.

In the study, reported in the journal The BMJ, the team analysed published evidence on the effectiveness of treatments for the common cold. They found that pain killers such as paracetamol and anti-inflammatory drugs (NSAIDs) also do not appear to improve nasal congestion or runny nose. 

Other treatments, such as steam inhalation, echinacea, vapour rub, eucalyptus oil, and increased fluid intake, are either not effective or have not been studied at all. "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," the team said. "Based on the currently available evidence, reassurance that symptoms are self limiting is the best you can offer patients, although short-term use of decongestants in adults can provide some relief from a blocked nose," they conclude.