indication

For short-term topical treatment of the inflammatory and pruritic manifestations of moderate to severe corticosteroid-responsive dermatoses of the scalp.

pharmacology

Like other topical corticosteroids, clobetasol has anti-inflammatory, antipruritic, and vasoconstrictive properties. It is a very high potency topical corticosteroid that should not be used with occlusive dressings. It is recommended that treatment should be limited to 2 consecutive weeks and therapy should be discontinued when adequate results have been achieved.

mechanism of action

The precise mechanism of the antiinflammatory activity of topical steroids in the treatment of steroid-responsive dermatoses, in general, is uncertain. However, corticosteroids are thought to act by the induction of phospholipase A₂ inhibitory proteins, collectively called lipocortins. It is postulated that these proteins control the biosynthesis of potent mediators of inflammation such as prostaglandins and leukotrienes by inhibiting the release of their common precursor arachidonic acid. Arachidonic acid is released from membrane phospholipids by phospholipase A₂. Initially, however, clobetasol, like other corticosteroids, bind to the glucocorticoid receptor, which complexes, enteres the cell nucleus and modifies genetic transcription (transrepression/transactivation).

toxicity

Oral LD₅₀ in rat and mouse is >3000 mg/kg. Topically applied clobetasol can be absorbed in sufficient amounts to produce systemic effects. Symptoms of overdose include thinning of skin and suppression of adrenal cortex (decreased ability to respond to stress).

biotransformation

Metabolized, primarily in the liver, and then excreted by the kidneys.

absorption

Topical corticosteroids can be 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.

route of elimination

Corticosteroids are metabolized primarily in the liver and are then excreted by the kidneys. Some of the topical corticosteroids, including clobetasol propionate and its metabolites, are also excreted into the bile.

drug interactions

Aldesleukin: Corticosteroids such as clobetasol may diminish the antineoplastic effect of aldesleukin. Avoid conccurent use of corticosteroids with aldesleukin.

Telaprevir: Corticosteroids such as clobetasol may decrease the serum concentration of telaprevir. Telaprevir may increase the serum concentration of corticosteroids. Concurrent use of telaprevir and systemic corticosteroids is not recommended. When possible, consider alternatives, and if such a combination is necessary, use extra caution, monitoring patients for excessive systemic steroid effects as well as for diminished telaprevir effects.