Chemical formula: C₃₁H₄₈O₆ Molecular mass: 516.709 g/mol PubChem compound: 3000226
Fusidic acid belongs to a unique group of antibiotics, the fusidanes, which act to inhibit bacterial protein synthesis by blocking the lengthening of factor G. This is to prevent it from associating with ribosomes and GTP, thus preventing energy supply to the synthesis process.
Fusidic acid and its salts are potent anti-staphylococcal agents with unusual ability to penetrate tissue. Bactericidal levels have been assayed in bone and necrotic tissue. Concentrations of 0.03-0.12 mcg/ml inhibit nearly all strains of staphylococcus aureus. Fusidic acid is active against staphylococcus epidermidis and methicillin resistant staphylococci.
Fusidic acid eye drops are active against a wide range of gram-positive organisms, particularly Staphylococcus aureus. Other species against which fusidic acid eye drops have been shown to have in vitro activity include Streptococcus, Neisseria, Haemophilus, Moraxella and Corynebacteria.
Resistance for fusidic acid can vary geographically and information about local resistance patterns should be obtained through a local microbiology laboratory. In general, resistance occurs in 1-10% of Staphylococcus aureus and 10-20% of coagulase negative staphylococci. Cross-resistance between Fusidic acid 20mg/g cream and other antibiotics has not been reported.
The sensitivity of organisms to fusidic acid is based on the in vitro sensitivity and plasma concentrations that are achieved after systemic therapy. Local treatment causes higher peak concentrations as compared to plasma. However, it is not known how the kinetics of the cream after local application may change the effectiveness of the cream.
The following MIC values are recommended to distinguish sensitive and non-sensitive germs: S≤1 µg/ml and R>1 µg/ml. This breakpoint should be used for the systemic use of fusidic acid. In general, no breakpoints are established for the topical use of antibiotics.
Commonly susceptible species: Staphylococcus aureus and Staphylococcus epidermis (including methycillin resistant and beta lactamase producing strains); Corynebacterium minutissimum; Clostridium spp.; Peptococcus spp.; Peptostreptococcus spp.; Neiseria spp.; Bacteroides fragilis.
Inherently resistant organisms: Streptococcus pyogenes; Streptococcus pneumoniae; Streptococci viridans; most gram negative bacilli including Haemophilus influenza; Enterobactericeae; Pseudomonas spp.; Escherichia coli and Klebsiella pneumoniae.
Blood levels are cumulative, reaching concentrations of 50-100 mcg/ml after oral administration of 1.5 g daily for 3 to 4 days.
Fucidin is excreted mainly in the bile, little or none being excreted in the urine.
In severe or deep-seated infections and when prolonged therapy may be required, systemic fucidin should generally be given concurrently with other anti-staphylococcal antibiotic therapy.
In vitro studies show that fusidic acid can penetrate intact human skin. The degree of penetration depends on factors such as the duration of exposure to fusidic acid and the condition of the skin.
Fusidic acid is excreted mainly in the bile with little excreted in the urine.
The sustained release formulation of fusidic acid eye drops ensures a prolonged contact with the conjunctival sac. Twice daily application provides sufficient fusidic acid concentrations in all relevant tissues of the eye. Fusidic acid penetrates well into the aqueous humour.
There are no pre-clinical data.
© All content on this website, including data entry, data processing, decision support tools, "RxReasoner" logo and graphics, is the intellectual property of RxReasoner and is protected by copyright laws. Unauthorized reproduction or distribution of any part of this content without explicit written permission from RxReasoner is strictly prohibited. Any third-party content used on this site is acknowledged and utilized under fair use principles.
