It’s commonly been stated that it’s important to finish your course of antibiotics (whether “your” refers to a person or animal), as a means of reducing the risk of developing antibiotic resistance. That’s never made much sense to me, since more antibiotic exposure is more likely to lead to a risk of resistance emerging. However, it’s been dogma.  The issue was addressed a few years ago in the ACVIM Consensus Statement on Antimicrobial Use in Animals. It also comes up in some working group that I’m in regarding antimicrobial use in humans and in animals, as messaging is starting to move away from “complete the course.” It’s a challenge though, since we don’t want treatment stopped too early (reducing effectiveness), but we also don’t want treatment to continue for days after it’s not needed.

A recent article in the BMJ, “The antibiotic course has had its day”(Llewelyn et al 2017) hits on the same topic. I’d recommend reading the whole article if you’re interested in the subject. Some of the more interesting aspects and comments are outlined below (italics are verbatim text from the paper):

  • However, the idea that stopping antibiotic treatment early encourages antibiotic resistance is not supported by evidence, while taking antibiotics for longer than necessary increases the risk of resistance.
    • Yet, there is often clinician fear. Basically, sometimes (consciously or not) people think that if the patient fails to respond to treatment, it’s a failure and is the clinician’s fault if they went with a short treatment course. If antibiotic resistance developed because of an excessive course of antibiotics, that’s seen as the drug’s fault, forgetting it’s the clinician that prescribed it. Fear of immediate and obvious patient outcome problems (even when unsubstantiated) typically overwhelm less obvious concerns about resistance.
  • Fundamental to the concept of an antibiotic course is the notion that shorter treatment will be inferior. There is, however, little evidence that currently recommended durations are minimums, below which patients will be at increased risk of treatment failure.
  • Historically, antibiotic courses were set by precedent, driven
by fear of undertreatment, with less concern about overuse. For many indications, recommended durations have decreased as evidence of similar clinical outcomes with shorter courses has been generated.
    • This applies in veterinary medicine too. I work with a few guidelines initiatives and getting people to buy into shorter durations has been a challenge. We’re making progress but fear of undertreating persists in some people.
  • For most indications, studies to identify the minimum effective treatment duration simply have not been performed.
  • Of note, a recent clinical trial found that using fever resolution to guide stopping antibiotics in community acquired pneumonia halved the average duration of antibiotic treatment without affecting clinical success.
    • This raises some interesting thoughts about when to stop. Focusing on how people feel or what they see in their animals as an indicator to stop may provide a more appropriate, tailored treatment, by stopping when the infection is gone. Sometimes. For some diseases, the time to stop is probably the time that the patient feels better or signs such as fever abate. However, there are probably others that need slightly longer treatment, since improvement in signs of disease doesn’t necessarily mean the infection is completely controlled. Here’s where more research is needed.

Their conclusion:

Research is needed to determine the most appropriate simple alternative messages, such as stop when you feel better. Until then, public education about antibiotics should highlight the fact that antibiotic resistance is primarily the result of antibiotic overuse and is not prevented by completing a course. The public should be encouraged to recognise that antibiotics are a precious and finite natural resource that should be conserved. This will allow patient centred decision making about antibiotic treatment, where patients and doctors can balance confidence that a complete and lasting cure will be achieved against a desire to minimise antibiotic exposure unimpeded by the spurious concern that shorter treatment will cause antibiotic resistance.

  • Maureen Anderson

    As stated, stopping treatment when a patient feels better may be one of the ways to reduce antibiotic use, but stopping the course raises another concern – what does the patient do with the leftover antibiotics? It is all too tempting to “save them for next time” even though the cause of illness the next time may be quite different, or not even bacterial. This leaves patients with unfettered access to drugs whose use should be supervised by a healthcare professional to ensure they are being used in the most effective manner possible, and not, for example for treating viral infections such as cold and flu (an all too common occurrence that almost certainly does contribute to antimicrobial resistance).