Mean peak plasma clobetasol propionate concentrations of nanograms/ml occurred in one study eight hours after the second application (13 h after an initial application) of 30 g clobetasol propionate % ointment to normal individuals with healthy skin. Following the application of a second dose of 30 g clobetasol propionate cream %, mean peak plasma concentrations were slightly higher than the ointment and occurred 10 h after application. In a separate study, mean peak plasma concentrations of approximately nanograms/ml and nanograms/ml occurred respectively in patients with psoriasis and eczema three hours after a single application of 25 g clobetasol propionate % ointment.
Like other topical corticosteroids, clobetasol propionate has anti-inflammatory, antipruritic, and vasoconstrictive properties. The mechanism of the anti-inflammatory activity of the topical steroids, in general, is unclear. However, corticosteroids are thought to act by the induction of phospholipase A 2 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.