Pharmacotherapeutic Group: Corticosteroids, potent, combinations with antibiotics - Betamethasone and antibiotics. ATC Code: D07CC01.
Pharmacology: Pharmacodynamics: Mechanism of action: Topical corticosteroids act as anti-inflammatory agents via multiple mechanisms to inhibit late phase allergic reactions including decreasing the density of mast cells, decreasing chemotaxis and activation of eosinophils, decreasing cytokine production by lymphocytes, monocytes, mast cells and eosinophils, and inhibiting the metabolism of arachidonic acid.
Neomycin interferes with bacterial protein synthesis by binding to 30S ribosomal subunits.
Pharmacodynamic effects: Topical corticosteroids have anti-inflammatory, antipruritic, and vasoconstrictive properties.
Neomycin has a bactericical action against many Gram-negative bacteria but it lacks activity against Pseudomonas aeruginosa. It has partial activity against Gram-positive bacteria. It is used topically in the treatment of infections of the skin, ear, and eye due to susceptible staphylococci and other organisms.
Pharmacokinetics: Absorption: Topical corticosteroids can be systemically absorbed from intact healthy skin. The extent of percutaneous absorption of topical corticosteroids is determined by many factors, including the vehicle and the integrity of the epidermal barrier. Occlusion, inflammation and/or other disease processes in the skin may also increase percutaneous absorption.
The use of pharmacodynamic endpoints for assessing the systemic exposure of topical corticosteroids is necessary due to the fact that circulating levels are well below the level of detection.
Absorption of neomycin has been reported to occur from wounds and inflamed skin. It is poorly absorbed from the gastrointestinal tract when administered orally.
Distribution: Absorbed neomycin distributes to tissues and concentrates in the renal cortex.
Metabolism: Once absorbed through the skin, topical corticosteroids are handled through pharmacokinetic pathways similar to systemically administered corticosteroids. They are metabolized, primarily in the liver.
Elimination: Topical corticosteroids are excreted by the kidneys. In addition, some corticosteroids and their metabolites are also excreted in the bile.
Absorbed neomycin is rapidly excreted by the kidneys as parent compound. It has been reported to have a half-life of 2 to 3 hours.
Toxicology: Pre-clinical Safety Data: Nonclinical studies have not been conducted with BETNOVATE-N.
Betamethasone valerate and neomycin sulphate individually have been evaluated in animal toxicity tests, and the following statements reflect the information available on the individual components.
Genotoxicity: Neomycin sulphate: Neomycin was negative in the Ames test, HGPRT mutations assay in Chinese hamster ovary (CHO) cells and mouse bone marrow micronucleus test.
Pregnancy: Betamethasone 17-valerate: Subcutaneous administration of betamethasone 17-valerate to mice or rats at doses ≥0.1 mg/kg/day or rabbits at doses ≥12 micrograms/kg/day during pregnancy produced foetal abnormalities including cleft palate.