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Antibiotics of no use in older people with cough

By Lilian Anekwe

Antibiotics provide little benefit for older people with infections that cause a long-term cough, according to the results of a new, good-quality study.

What do we know already?

At this time of year, coughs are common and can be annoying and sometimes distressing. They can make your chest hurt and disturb your sleep. Coughs are usually caused by infections of the respiratory tract (any infection of the sinuses, throat, airways, or lungs). Indeed, lower respiratory tract infections are among the most common reasons people go to see their nurse or GP.

Often, the infections that cause a cough are the product of a virus. We know that viruses, and the infections that they cause, can’t be treated with antibiotics. Antibiotics kill bacteria, so they are only useful for infections that are caused by bacteria. Even then, they may not help your symptoms or reduce how long you have symptoms by very much.

There is concern that, particularly in older people, respiratory tract infections caused by bacteria are more likely to cause complications and health problems, like pneumonia. So, should we use antibiotics to treat older people with a cough that lasts for a long time?

Researchers looked at this question by randomly assigning 2,100 people with a lower respiratory tract infection and a cough (that lasted less than 28 days) to one of two treatments. One half of the group took an antibiotic called amoxicillin three times a day for seven days, while the other half took a dummy pill (a placebo). The researchers then looked at how long people had a cough they rated as “moderately bad” or worse, and how likely their cough was to get worse after they had treatment.

What does the new study say?

People who took a placebo were no more likely to have worse symptoms than people who took an antibiotic. They were also no more likely to have a cough that was moderately bad, or worse, for longer than people who took antibiotics.

People who took an antibiotic were less likely to get new symptoms, and their cough was less likely to get worse than people who took a placebo. Around 16 in 100 people who took an antibiotic had new symptoms or symptoms that got worse, compared with around 19 in 100 who took a placebo. This difference is only just large enough to exclude being caused by random chance. There was no additional benefit from taking antibiotics when researchers looked only at people aged 60 years and older.

Side effects such as feeling sick, a rash, or diarrhoea were more common in people who took antibiotics.

How reliable is the research?

This was a randomised controlled trial, which is one of the best ways to compare how well treatments work. Neither the researchers nor the people in the study knew which treatment they were getting. This means the results should be fairly reliable. This study is much larger than previous studies that have looked at antibiotics for cough, so this makes it more reliable than earlier research.

What does this mean for me?

This study suggests that there is no benefit from taking antibiotics if you have a lower respiratory tract infection or a cough, even for a cough that lasts up to a month. This is an important message to remember at this time of year, when coughs and infections become more common. The one exception the researchers noted is if your doctor suspects that your cough may be caused by something else, like pneumonia. But most coughs are caused by viruses and will get better and go away in their own in time.


Little P, Stuart B, Moore M, et al. Amoxicillin for acute lower-respiratory-tract infection in primary care when pneumonia is not suspected: a 12-country, randomised, placebo-controlled trial. Lancet. Published online 19 December 2012.

Dec 19, 2012