What is flucloxacillin (Flucloxacillin)?

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Last updated: April 30, 2025View editorial policy

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From the Guidelines

Flucloxacillin is an antibiotic medication that belongs to the penicillin class, specifically designed to treat infections caused by bacteria that are resistant to standard penicillin, and is commonly prescribed for skin and soft tissue infections, respiratory tract infections, bone and joint infections, and other conditions where penicillinase-producing bacteria are suspected, with a typical adult dose of 500mg taken four times daily, as recommended for Staphylococcus aureus (MSSA) infections 1.

Key Points

  • Flucloxacillin works particularly well against Staphylococcus aureus infections, including methicillin-sensitive strains (MSSA) 1.
  • The typical adult dose ranges from 250-500mg taken four times daily, while children receive weight-based dosing 1.
  • Treatment duration usually spans 5-14 days depending on the infection severity 1.
  • Flucloxacillin works by inhibiting bacterial cell wall synthesis, preventing bacteria from forming protective barriers and ultimately causing their death.
  • It should be taken on an empty stomach, ideally one hour before or two hours after meals, to maximize absorption.
  • Common side effects include gastrointestinal disturbances, rash, and rarely liver function abnormalities.
  • Patients with penicillin allergy should avoid this medication, and it may interact with certain other drugs, so a complete medication history should be provided to healthcare providers.

Clinical Use

  • Flucloxacillin is commonly prescribed for skin and soft tissue infections, respiratory tract infections, bone and joint infections, and other conditions where penicillinase-producing bacteria are suspected 1.
  • In cases of mild infections, oral flucloxacillin may be the initial treatment of choice, while broader spectrum antibiotics may be considered in patients with moderate or severe infections 1.

Important Considerations

  • The choice of antibiotic therapy should be based on the likely isolated causative pathogens and their antibiotic susceptibilities, as well as the clinical severity of the infection 1.
  • Patients with a history of penicillin allergy should be cautious when using flucloxacillin, and alternative antibiotics may be considered in such cases 1.

From the Research

Definition and Characteristics of Flucloxicillin

  • Flucloxicillin is an antibiotic that belongs to the class of penicillinase-resistant penicillins 2, 3.
  • It is used to treat infections caused by Staphylococcus aureus, including methicillin-susceptible S. aureus (MSSA) infections 2, 4, 5.
  • Flucloxicillin is effective against bacteria that produce penicillinase, an enzyme that breaks down penicillin 3.
  • It is available in oral and injectable forms, with the sodium form being used in pharmaceutical formulations 3.

Uses and Efficacy of Flucloxicillin

  • Flucloxicillin is used to treat various types of infections, including skin and soft tissue infections, meningitis, and bloodstream infections 2, 4, 5, 6.
  • It has been shown to be effective in treating MSSA infections, with cure rates ranging from 75% to 90% 4, 5.
  • Flucloxicillin is often used as a first-line treatment for MSSA infections, particularly in intensive care units 4.
  • However, its use may be limited by adverse events, such as those leading to discontinuation of treatment in 13% of patients in one study 6.

Analytical Methods for Flucloxicillin

  • Various analytical methods have been developed to determine the presence and concentration of flucloxicillin in pharmaceutical products and biological matrices 3.
  • High-performance liquid chromatography (HPLC) is a commonly used method, but it has limitations such as the use of toxic solvents and long analysis times 3.
  • There is a need for more sustainable and environmentally friendly analytical methods for flucloxicillin 3.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Flucloxacillin: A Review of Characteristics, Properties and Analytical Methods.

Critical reviews in analytical chemistry, 2019

Research

Flucloxacillin treatment of Staphylococcus aureus meningitis.

European journal of clinical microbiology & infectious diseases : official publication of the European Society of Clinical Microbiology, 2007

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Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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