Commonly Used Antibiotics Azithromycin and Doxycycline Not Generally Effective Treatments for COVID-19, Finds Trial

A new trial has revealed that two commonly used antibiotics that are being used by some doctors in the hope of treating COVID-19 in the early stages of the illness are not generally effective treatments for the disease.

Azithromycin and doxycycline are two commonly used antibiotics that were investigated as separate treatments in the UK-wide Platform Randomized trial of INterventions against COVID-19 In older people (PRINCIPLE) trial by researchers from the University of Oxford (Oxford, UK). After reviewing interim analyses of both the azithromycin and doxycycline arms of the PRINCIPLE trial, the independent Trial Steering Committee has advised the trial investigators, who concluded that there is no beneficial effect in patients aged over 50 years who are treated with either antibiotic at home in the early stages of COVID-19. This is because interim data analyses show that neither treatment reduces the time taken for people to first report that they feel recovered sufficiently to achieve meaningful clinical benefit. The PRINCIPLE trial was established as a flexible, platform randomized clinical trial to test a range of potential treatments for COVID-19 that might be suitable for use in the community to help people recover more quickly and prevent the need for hospital admission. The trial did not look at the effects of these drugs in patients who were already admitted to hospital with COVID-19.


“Azithromycin and doxycycline have anti-inflammatory, antibacterial and possibly antiviral effects, and so were considered as potential treatments for COVID-19 in the community,” said Professor Chris Butler from the University of Oxford’s Nuffield Department of Primary Care Health Sciences and Co-Lead of the PRINCIPLE trial. “While we are completing the analysis of the full range of study outcomes, and in different patient groups, our findings show that a three-day course of azithromycin or a seven-day course of doxycycline has no important clinical benefit in terms of the time taken to feeling recovered, and so will not help most patients with COVID-19 in the early stages their illness. These are two important findings, as both azithromycin and doxycycline have been used for treating COVID-19 in the community even in the absence of suspected bacterial pneumonia, so this practice should now be re-considered - particularly because overuse of antibiotics in the community can fuel the emergence of antimicrobial resistance.”

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