No Evidence Stopping Antibiotics Early Increases Resistance

Theresa Bebbington

July 28, 2017

The message given by doctors to 'complete the course' when taking antibiotics should be dropped, experts say.

They argue that it is not backed by evidence and should be replaced.

Antibiotics are important for fighting off infections, but there is a growing global concern about the number of cases in which bacteria have become resistant to these medicines.

To avoid an increase in antibiotic resistance, it is essential to reduce unnecessary antibiotic use.

The current recommendation by the World Health Organisation (WHO) is to "always complete the full prescription, even if you feel better, because stopping treatment early promotes the growth of drug-resistant bacteria".

In the UK, in fact, this advice is included in the curriculum for secondary school children.

However, several experts in infectious diseases are urging policy makers, educators and doctors to reconsider the advice given to patients when prescribing antibiotics.

Martin J Llewelyn, professor of infectious diseases at Brighton and Sussex Medical School, and his colleagues have presented their analysis against the 'complete the course' message in an article published in the BMJ.

They say that there is no evidence that stopping antibiotics early encourages antibiotic resistance – and that taking them for longer than needed increases the risk of resistance.

Antibiotic Resistance

In their analysis, the authors report that concerns about not taking enough antibiotics leading to resistance in treatment first occurred in the 1940s.

Alexander Fleming's 1945 Nobel Prize acceptance speech, for example, included his view that if insufficient penicillin is given for a streptococcal throat infection, a resistant form of the infection could be passed on to another person. It turned out that the streptococcal bacteria responsible for throat infections have yet to develop a resistance to penicillin.

It is true that for certain infections – such as tuberculosis, gonorrhoea and malaria – when the microorganisms causing the infection replicate, antibiotic-resistant mutations can occur if an inadequate antibiotic dose is given during treatment or only one medicine is used. This is known as targeted selection. However, most bacteria do not develop resistance through targeted selection.

Instead, taking antibiotics can affect the usually harmless flora, or germs, that are normally found on our skin and membranes or in our guts, and this allows for opportunistic resistant species or strains to replace them. This is known as collateral selection. The longer these opportunistic species or strains are exposed to antibiotics, the authors argue, the more of a chance that antibiotic resistance can occur.

Llewelyn and his colleagues say that because of historical concern about under-treatment and the previous lack of concern about overuse, the recommended durations or courses may be too long. For most indications, "studies to identify minimum effective treatment duration simply have not been performed".

They do note that there are some cases, such as otitis media (ear infection), where a shorter duration of treatment may not be as effective, but also point out that there is a lower risk of further or resistant infection in some pneumonia patients receiving shorter courses of antibiotics. Clinical trials can help establish the optimised duration for antibiotic treatment.

Less Is More

They authors report that, for opportunistic pathogens, "no clinical trials have shown increased risk of resistance among patients taking shorter treatments." They also argue that shorter treatment can mean a reduced risk of developing a resistant infection.

Inside hospitals, tests can be used to determine when to stop treatment, but this is not feasible outside of hospital.

Llewelyn and his colleagues suggest disregarding the WHO advice and replacing it with advice to stop treatment when the patient feels better. They note that in one clinical trial, stopping antibiotics for treating pneumonia when the patient's fever resolved halved the average duration of antibiotic treatment and did not affect recovery.

Public Health England has already replaced the old 'complete the course' message with 'exactly as prescribed'. However, the authors are now calling for dropping of the 'complete the course' message altogether and want officials to actively acknowledge that it is incorrect.

They also believe the public will be behind this approach, saying: "Completing the course goes against one of the most fundamental and widespread medication beliefs people have, which is that we should take as little medication as necessary."

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