Is flucoxacillin (Flucloxacillin) effective for treating cellulitis?

From the Guidelines

Flucoxacillin is an effective antibiotic for treating cellulitis, particularly for infections caused by Staphylococcus aureus and Streptococcus species, with a recommended treatment duration of 5-7 days 1.

Key Considerations

• The most recent guidelines from the National Institute for Health and Care Excellence (NICE) and the American College of Physicians recommend a course of 5 to 7 days for uncomplicated cellulitis 1.
• The DANCE (Duration of Antibiotic Therapy for Cellulitis) RCT compared a 6-day course of flucloxacillin with the standard 12-day course and found overall similar rates of cure, suggesting that a shorter course may be adequate 1.
• 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.
• For patients with penicillin allergy, alternatives include clindamycin or clarithromycin.
• If MRSA is suspected or confirmed, different antibiotics like trimethoprim-sulfamethoxazole or doxycycline may be needed.

Treatment Recommendations

• The typical adult dose of flucoxacillin is 500mg taken orally four times daily (every 6 hours) for 5-7 days.
• For severe infections, higher doses of 1-2g every 6 hours may be required, potentially administered intravenously in hospital settings.
• Patients should elevate the affected limb when possible, stay hydrated, and seek immediate medical attention if fever develops, the affected area expands rapidly, or if symptoms worsen despite 48 hours of treatment.

Important Considerations

• The optimal duration of antibiotic therapy for skin and soft tissue infections (SSTIs) is still being evaluated, and further study is needed to confirm the effectiveness of shorter treatment courses 1.
• Clinicians should consider extending treatment if the infection has not improved after 5 days, and should be aware of the potential for MRSA infection, particularly in patients with certain risk factors 1.

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. 2

From the Research

Effectiveness of Flucoxacillin for Treating Cellulitis

• Flucoxacillin is effective against methicillin-sensitive Staphylococcus aureus and Streptococcus, which are common causes of cellulitis 3, 4.
• The treatment of uncomplicated cellulitis should be directed against Streptococcus and methicillin-sensitive S. aureus, and flucoxacillin is a suitable option 3.
• A study found that Staphylococcus aureus was the most common organism isolated from primary pyodermas, including cellulitis, and flucoxacillin (or cloxacillin) was effective against this organism 5.
• Another study suggested that acute non-necrotising cellulitis is mostly of streptococcal origin, and penicillin or a penicillin-like antibiotic such as flucoxacillin can be used as first-line therapy 6.
• However, there is limited evidence directly comparing the effectiveness of flucoxacillin alone versus flucoxacillin combined with penicillin V for the treatment of cellulitis, as no randomized-controlled trials were found 7.

Considerations for Treatment

• The diagnosis of cellulitis is based primarily on history and physical examination, and treatment should be initiated promptly 3, 4.
• The choice of antibiotic should be guided by the suspected causative organism and local resistance patterns 3, 5.
• Flucoxacillin may be a suitable option for the treatment of cellulitis, but it is essential to consider the potential for resistance and adjust treatment accordingly 5.