-2%
Fusidic acid + Betamethasone combines the potent topical antibacterial activity of fusidic acid with the anti-inflammatory and anti-pruritic activity of the moderately potent corticosteroid betamethasone valerate. When applied topically, fusidic acid is effective against Staphylococci, Streptococci, Corynebacteria, Neisseria, and certain Clostridia and Bacteroides. The antibacterial activity of fusidic acid is not diminished in the presence of betamethasone.
Fusidic acid exhibits activity primarily against Gram-positive bacteria, including Streptococcus, Staphylococcus aureus, and Corynebacterium minutissimum. Its antibacterial effect is achieved through the inhibition of bacterial protein synthesis, where it disrupts the transfer of amino acids from aminoacyl-tRNA to the growing peptide chain on ribosomes.
Betamethasone, a potent corticosteroid, acts by inducing the synthesis of lipocortin, a protein that inhibits the enzyme phospholipase Aâ‚‚. This inhibition suppresses the formation of inflammatory mediators such as prostaglandins, kinins, and histamine, thereby reducing inflammation, redness, and itching.
Pharmacokinetics:
Fusidic acid demonstrates the ability to penetrate intact human skin, with approximately 2% of the topically applied dose being absorbed. The extent of absorption varies depending on factors like exposure duration and the skin’s condition. It is primarily excreted via bile, with minimal elimination through urine.
The absorption and potency of topical corticosteroids such as betamethasone are influenced by the formulation vehicle. Higher absorption levels are typically observed in areas with thin or compromised skin—such as the face, groin, axillae, or inflamed regions (e.g., atopic dermatitis lesions).