The Myth of Antibiotics: 'Complete the Course' Won't Stop Resistance, Researchers Say

Amoxicillin penicillin antibiotics are seen in a pharmacy at a free medical and dental health clinic in Los Angeles on April 27, 2016. Researchers in a new study urge doctors, educators and policy makers to drop the deeply embedded “complete the course” message. Lucy Nicholson/Reuters

Doctors have long urged patients to adhere strictly to antibiotic prescriptions, asserting that the entire course should be completed regardless of whether their symptoms have been resolved. Not doing so, conventional wisdom has held, brings the risk of increasing bacterial resistance to antibiotics.

Antibiotic resistance is one of the most serious global threats to both human health and agriculture, and finding ways to avoid it is a priority. When it comes to treatment for our bacterial infections, it has long been thought that cutting a course short eradicates most but not all of the bacteria behind the illness, thus leaving the door open for the pathogens to develop the ability to evade attack by the drugs.

Recently, that approach has been called into question. Most notably, Louise Rice, who chairs the department of medicine at the Warren Alpert Medical School at Brown University, has led the movement to re-examine this directive. Now, this paradigm shift has taken yet another step. In a newly published issue of BMJ, a major medical journal, researchers argue that telling patients to complete a full course of antibiotics to avoid resistance is not backed by evidence.

Related: After years of debate, the FDA curtails antibiotic use in livestock

In fact, Martin Llewelyn and his colleagues at Brighton and Sussex Medical School in the United Kingdom say in the paper there is evidence that, in many situations, stopping antibiotics sooner is a safe and effective way to reduce overuse, while taking antibiotics for longer than necessary increases the risk of resistance.

The researchers urge doctors, educators and policy makers to drop the "complete the course" message and communicate with patients that the longstanding way of thinking is incorrect. For common bacterial infections, for example, no evidence exists that stopping antibiotic treatment early increases a patient's risk of resistant infection.

"We found that the common advice that it is 'important for patients to finish their course of antibiotics in order to avoid the emergence of antibiotic resistance' appears to be a modern myth, deeply embedded in our culture but based on no sound scientific evidence," Tim Peto, professor of infectious diseases at the NIHR Biomedical Research Center, Oxford University the medical school, tells Newsweek.

Their main argument for changing how doctors discuss antibiotic courses with patients is that shorter treatment can be better for individual patients. Not only does an individual patient's risk of resistant infection depend on his/her previous antibiotic exposure, but reducing that exposure via shorter treatment is associated with reduced risk of resistant infection and better clinical outcome, they say.

As the authors note, antibiotics are vital to modern medicine and resistance is a global, urgent threat to human health. But completing a course, they add, defies one of the most fundamental and widespread medication beliefs: that we should take as little medication as necessary.

Traditionally, antibiotics are prescribed for recommended durations or courses. Fundamental to the concept of an antibiotic course is the notion that shorter treatment will be inferior.

Concern that giving too little antibiotic treatment could select for resistance can be traced back to 1941, when Howard Florey's team treated Albert Alexander's staphylococcal sepsis with penicillin. They stretched out all the penicillin they had over four days by repeatedly recovering the drug from the patient's urine. When the drug ran out, the clinical improvement they had noted reversed, and he subsequently succumbed to his infection. As the researchers note in their new study, there was no evidence that this was because of resistance, but the experience may have planted the idea that prolonged therapy was needed to avoid treatment failure.

More recently, in materials supporting Antibiotic Awareness Week 2016, the World Health Organization advised patients to "always complete the full prescription, even if you feel better, because stopping treatment early promotes the growth of drug-resistant bacteria." Similar advice appears in national campaigns in Australia, Canada, the United States and throughout Europe. In the U.K., it's included as fact in the curriculum for secondary school children, the authors note.

They also note there are exceptions for some types of antibiotics, including those used to treat tuberculosis.

They call for research to determine the most appropriate, simple alternative messages, such as stop when you feel better, and advise policy makers to publicly and actively state that the old message was not evidence-based and is incorrect. Clinical trials are required to determine the most effective strategies for optimizing duration of antibiotic treatment.

"The public," they add, "should also be encouraged to recognize that antibiotics are a precious and finite natural resource that should be conserved by tailoring treatment duration for individual patients."