It has previously been emphasized that courses of antibiotics must not be cut short, as this risks the survival of the most resistant bacteria. The prevailing view was that shortened courses contribute to increased antibiotic resistance – one of the greatest threats to global health today.
More recently, however, increasing importance has been placed on reducing unnecessary exposure to antibiotics through shorter courses. The current view is that prolonged use of antibiotics can favor resistant bacteria, including bacteria that do not cause the infection. Shorter treatment periods can therefore, in some cases, reduce this risk. Furthermore, shorter courses are considered to offer benefits beyond reduced resistance, such as fewer side effects and better preservation of the body’s natural bacterial flora.
A commentary in The American Journal of Bioethics addresses an interesting question raised by this new focus on shorter antibiotic courses. Three researchers from Uppsala University, including Mirko Ancillotti, discuss a proposal published in the same issue of the journal. The proposal has two parts. The first part is that physicians should generally avoid prescribing courses longer than guidelines recommend. The second part of the proposal is that if clinical studies show that a guideline recommends an unnecessarily long course – a shorter course is effective – then these new findings create a moral obligation for physicians to deviate from the guideline by prescribing a shorter treatment than recommended.
Mirko Ancillotti and his co-authors agree with the first part of the proposal: physicians should generally avoid prescribing courses longer than recommended by the guidelines. However, they view the second part of the proposal as less clear. When can new findings create a moral obligation to prescribe shorter courses of treatment than the guidelines recommend? It is difficult to isolate the effect of treatment duration in clinical studies where multiple factors vary, so the evidence is not always as strong as it might appear. Moreover, a shorter course – even if studies suggest it is effective – could still entail an increased risk of relapse at a later stage. Above all, the assessments physicians must make are more complex than simply evaluating the strength of the evidence. The physician must assess the relevance of the evidence to the specific treatment situation, and the risk of increased antibiotic resistance must be weighed against the risks that a shorter treatment might pose to the individual patient in the clinical context. Such assessments may well make it reasonable for a physician to choose to deviate from the guidelines. But can the evidence create an obligation to choose a shorter antibiotic course? Can it make it morally wrong to follow the guidelines?
Towards the end of the commentary, the authors propose a criterion for when a shorter course is not merely a reasonable option but a moral obligation. Their criterion is complex and encompasses more than just the strength of the evidence. The evidence must isolate the effect of treatment duration and be applicable to the clinical situation at hand. However, evidence alone cannot create a moral obligation, no matter how strong it is. A convincing argument is also required to demonstrate that the benefits of reduced antibiotic exposure in the specific case outweigh the remaining uncertainties regarding recovery and relapse. Slightly simplified, the authors argue that prescribing below the guideline becomes a moral obligation when following the guideline is no longer professionally defensible for the physician.
The authors indicate that it would be unfortunate if the previous generalization – “longer treatment duration is better” – were simply replaced by the opposite generalization: “shorter is better.” Their commentary points to the need for a more nuanced approach to antibiotic resistance. Read the commentary here: When Does Evidence Create a Moral Obligation to Depart from Antibiotic Guidelines?
Written by…
Pär Segerdahl, Associate Professor at the Centre for Research Ethics & Bioethics and editor of the Ethics Blog.
Ancillotti, M., Andersson, D. I., & Sandegren, L. (2026). When Does Evidence Create a Moral Obligation to Depart from Antibiotic Guidelines? The American Journal of Bioethics, 26(9), 109–111. https://doi.org/10.1080/15265161.2026.2709544
