Is flucoxacillin (Flucloxacillin) effective for treating cellulitis?

From the Guidelines

Flucoxacillin is an effective antibiotic for treating cellulitis, particularly for patients with nonpurulent cellulitis, and should be used for a 5- to 6-day course, as recommended by the American College of Physicians 1, 2, 3, 4, 5, 6. The recommended adult dosage is 500mg taken orally four times daily (every 6 hours) for 5-7 days, though treatment may extend to 14 days depending on clinical response. Some key points to consider when using flucoxacillin for cellulitis include:

• Flucoxacillin should be taken on an empty stomach, at least 30-60 minutes before meals or 2 hours after eating, to maximize absorption.
• Common side effects include nausea, diarrhea, and rash.
• Flucoxacillin is effective against Staphylococcus aureus and Streptococcus species, which are the most common causative organisms in cellulitis.
• For patients with penicillin allergy, alternatives include clindamycin or clarithromycin.
• If MRSA is suspected or confirmed, or if the infection is not responding to flucoxacillin within 48 hours, alternative antibiotics should be considered.
• Patients should be advised to elevate the affected limb when possible, stay hydrated, and seek immediate medical attention if the infection worsens or if they develop fever, increasing pain, or spreading redness despite treatment. The DANCE (Duration of Antibiotic Therapy for Cellulitis) RCT compared a 6-day course of a penicillin (flucloxacillin) with the standard 12-day course and found overall similar rates of cure, but with wide CIs that could neither confirm nor refute shorter versus longer therapy 1. Further study is needed to evaluate the optimal duration of antibiotic therapy for SSTIs. However, based on the current evidence, a 5- to 6-day course of flucoxacillin is a reasonable treatment option for patients with nonpurulent cellulitis.

From the FDA Drug Label

The penicillinase-resistant penicillins are indicated in the treatment of infections caused by penicillinase-producing staphylococci which have demonstrated susceptibility to the drugs. The answer is: No, the FDA drug label does not explicitly state that flucloxacillin is effective for treating cellulitis.

• The label mentions treatment of infections caused by penicillinase-producing staphylococci, but does not specifically mention cellulitis. 7

From the Research

Effectiveness of Flucoxacillin for Treating Cellulitis

• Flucoxacillin is a commonly prescribed antibiotic for the treatment of cellulitis, particularly in Ireland and the United Kingdom 8.
• The treatment of uncomplicated cellulitis should be directed against Streptococcus and methicillin-sensitive S. aureus, and flucoxacillin is effective against these bacteria 9, 10.
• A systematic review found no randomized-controlled trials comparing flucloxacillin monotherapy with a combination of flucloxacillin and penicillin V in the ED management of cellulitis 11.
• A study protocol for a randomised controlled trial aimed to establish the non-inferiority of oral monotherapy (flucloxacillin alone) to dual therapy (flucloxacillin and phenoxymethylpenicillin) for the outpatient treatment of cellulitis in adults 8.
• The majority of non-purulent, uncomplicated cases of cellulitis are caused by β-hemolytic streptococci or methicillin-sensitive Staphylococcus aureus, and appropriate targeted coverage of this pathogen with oral antibiotics such as penicillin, amoxicillin, and cephalexin is sufficient 10.

Key Points

• Flucoxacillin is effective against Streptococcus and methicillin-sensitive S. aureus, which are the common causes of cellulitis 9, 10.
• There is a lack of randomized-controlled trials comparing different antibiotic regimens for the treatment of cellulitis 11.
• The treatment of cellulitis should be based on the clinical presentation and physical examination, and microbiological diagnosis is often unobtainable due to poor sensitivity of culture specimens 9, 10.
• Flucoxacillin can be used as a monotherapy for the treatment of uncomplicated cellulitis, but more research is needed to establish its non-inferiority compared to dual therapy 8.