Comparing short and standard antibiotic courses for leg cellulitis

A Blinded, Non-inferiority Phase III Trial of 5 Versus 7 Days of Oral Flucloxacillin in Primary Care Patients With Lower Limb Cellulitis

Phase 3 Interventional University of Southampton · NCT05584007

This study is testing if a 5-day course of antibiotics works just as well as the usual 7-day course for adults with leg cellulitis.

Quick facts

PhasePhase 3
Study typeInterventional
Enrollment356 (estimated)
Ages18 Years and up
SexAll
SponsorUniversity of Southampton Academic / other
Locations1 site (Southampton)
Trial IDNCT05584007 on ClinicalTrials.gov

What this trial studies

This clinical trial aims to evaluate whether a 5-day course of oral flucloxacillin is as effective as the standard 7-day course for treating cellulitis of the leg in adults. Participants will be randomly assigned to receive either the shorter or longer antibiotic treatment while also receiving usual care. The study will assess pain levels over a period of days 6-14 post-treatment, as well as the cost implications of the different treatment durations. Participants will complete daily questionnaires to share their experiences and symptoms during the trial.

Who should consider this trial

Good fit: Ideal candidates are adults aged 18 years or older with symptoms of cellulitis in one leg for 10 days or less and a pain rating of 3/10 or higher.

Not a fit: Patients with penicillin allergies, bilateral cellulitis, or those requiring immediate hospital admission will not benefit from this study.

Why it matters

Potential benefit: If successful, this study could lead to a more effective and cost-efficient treatment for cellulitis, reducing the duration of antibiotic use.

How similar studies have performed: Previous studies have explored antibiotic treatment durations for cellulitis, but this specific comparison of 5-day versus 7-day courses is novel.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Must be aged 18 years or older
* Currently showing symptoms of cellulitis (such as pain, tenderness, redness, other change in skin color, warmth to touch) in one leg for 10 days or less
* Pain rated as 3/10 or higher on a numerical rating scale (0-10) at baseline assessment
* Be willing to be randomized to either trial arm (5-day or 7-day treatment)
* Able to complete trial procedures in the English language.

Exclusion Criteria:

* Have penicillin allergy
* Have bilateral cellulitis
* Have had antibiotics for cellulitis within the past month
* Have post-operative cellulitis (within 30 days of operative procedures on the same leg)
* Have cellulitis resulting from human/animal bite injury
* Have Cellulitis associated with chronic (\>6 weeks) leg ulceration
* Require immediate hospital admission or out-patient intravenous antibiotic therapy

Where this trial is running

Southampton

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Cellulitis of LegPrimary careAntibiotic treatmentAntibiotic resistancePainCost consequences
Last reviewed 2026-06-09 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.