(CNN) The standing argument that failing to complete a course of antibiotics could fuel the rise of antibiotic resistance has little evidence, a group of United Kingdom researchers argue in a new paper. In an analysis published in the medical journal the BMJ on Thursday, they say that completing a course of antibiotics may instead increase the risk of resistance.
The "complete the course" advice given to patients taking antibiotics is "fallacious" and backed by little evidence, they state in their article, and could lead to antibiotic overuse -- and further resistance.
But other doctors urge caution, and say they aren't ready to change standard advice around taking antibiotics.
The opinion piece suggests that an alternative message, such as "stop when you feel better" could be developed. But the authors accept that more research is needed before this is implemented -- and that this may not apply to all infections.
"We're not at all saying that patients should stop when they feel like it or that patients should ignore their doctor's advice," Tim Peto, professor of medicine at the University of Oxford and a co-author of the article, told CNN.
But Peto believes that ending a course of antibiotics to prevent resistance is a counter-intuitive view and that there is "not enough knowledge" for doctors to know how long antibiotics should be prescribed for.
Current advice to complete your course of antibiotics stems from the early days of antibiotic use, the authors describe. They note that Alexander Fleming's Nobel speech in 1945 includes a vivid story of an imagined patient who takes an insufficient amount of penicillin, leading to a death in another patient who is infected and becomes resistant. "If you use penicillin, use enough," Fleming urged in the speech.
"No one has questioned (this advice) for all this time," said Peto.
"In the scientific world, it's an accepted view that there is too much usage of antibiotics and we want to minimize that. We want to only give them to people who need antibiotics to get better," he said.
The paper then concludes that the public should be encouraged to recognize that antibiotics are a precious and finite natural resource that should be conserved.
But the group's stance has received mixed responses from the medical community.
The Royal College of General Practitioners, a network of more than 52,000 family doctors in the UK, urged caution.
"It's important that we take new evidence around how to curb this on board, but we cannot advocate widespread behavior change on the results of just one study," said Professor Helen Stokes-Lampard, the group's chairwoman, in a statement.
Stokes-Lampard recommended that the public should continue following "complete the course" advice until more is known. "We would urge our patients not to change their behavior," she said, adding that changing the accepted "mantra" would "simply confuse people."
But she agreed that more clinical trials are needed to understand more about whether courses should be completed, and that people should then take any new evidence into account when guidelines are updated. "We're not at that stage yet," she warned.
The UK's National Health Service says antibiotic resistance is a significant threat to patient safety and both the NHS and World Health Organization presently advise people to complete their antibiotic courses.
But Jodi Lindsay, professor of microbial pathogenesis at St. George's, University of London, believes this new advice -- to stop taking antibiotics once you feel better -- is "sensible."
"The evidence for 'completing the course' is poor, and the length of the course of antibiotics has been estimated based on a fear of under-treating rather than any studies," she said, adding that there are a few exceptions of diseases when longer treatment courses are better, such as tuberculosis, which has a minimum treatment period of six months.
"It remains astonishing that apart from some specific infections and conditions, we still do not know more about the optimum duration of courses or indeed doses in many conditions," added Alison Holmes, professor of infectious diseases at Imperial College London. "Yet this dogma [to complete the course] has been pervasive and persistent."
Peto said more high-quality research is being done on the topic by experts within the field.
"The more one looks, the more we see that we can shorten the duration [of a prescription's length]," he said.
They're trying to avoid blanket statements because of illness such as tuberculosis, he said, but that illness is unusual.
"With normal family practice infections, we just don't know what the optimum length of time is that a patient should [take antibiotics for]," he said.
"What we want is to empower general practitioners to be able to shorten courses on a case-by-case basis if they feel that it's best for the patient."