An Expert-Level Report on Flucloxacillin

1. Executive Summary

Flucloxacillin, also known as floxacillin, is a narrow-spectrum, semisynthetic beta-lactam antibiotic belonging to the penicillin class. It is distinguished by its stability against staphylococcal beta-lactamases, which makes it particularly effective for treating infections caused by penicillinase-producing Gram-positive bacteria, most notably methicillin-sensitive Staphylococcus aureus (MSSA) and Streptococcus species. Its primary clinical applications include the treatment of a wide range of skin, soft tissue, bone, and respiratory infections. While generally well-tolerated, its safety profile warrants careful consideration due to the risk of rare but severe idiosyncratic adverse effects, including cholestatic liver injury and a potentially fatal interaction leading to high anion gap metabolic acidosis (HAGMA). A comprehensive understanding of its unique pharmacokinetic properties, its immune-mediated hepatotoxicity pathway, and its critical drug interactions is essential for its safe and effective clinical use.

The medication's regulatory and clinical use varies significantly by region. Its historical development in the United Kingdom led to its widespread adoption there, in Australia, and in New Zealand, in contrast to its limited use in the United States and Canada where similar agents like oxacillin and dicloxacillin are more prevalent. This report synthesizes available information to provide a detailed reference document covering Flucloxacillin's chemical properties, pharmacology, therapeutic applications, pharmacokinetics, and a detailed analysis of its complex safety profile.

2. Introduction to Flucloxacillin