Fusidic acid is active against a wide range of gram-positive organisms, particularly Staphylococci. Other species against which fusidic acid exerts high clinical activity include Streptococci, Pneumococci, Neisseria, Haemophilus, Moraxella and Corynebacteria.
No cross-resistance with fusidic acid and other clinically available antibiotics is shown, and fusidic acid is stable to bacterial β-lactamases.
The sustained-release formulation of Fucithalmic ensures prolonged contact with the conjunctival sac. Twice-daily application provides sufficient concentrations of fusidic acid in all relevant tissues of the eye. It penetrates well into the aqueous humour.
Fusidic acid is generally atoxic, and experience with its dermatological use shows a very low allergenic potential. No cross-allergy with other antibiotics is shown by patients treated with fusidic acid.