“May all be happy, may all be healed, may all be at peace and may no one ever suffer."
Corticosteroids play a role in cellular signaling, immune function, inflammation, and protein regulation; however, the precise mechanism of action in plaque psoriasis is unknown. Tazarotene is a retinoid prodrug which is convert d to its active form, tazarotenic acid, the carboxylic acid of tazarotene, by deesterification. Tazarotenic acid binds to all three members of the retinoic acid receptor (RAR) family: RARα, RARβ and RARγ, but shows relative selectivity for RARβ, and RARγ and may modify gene expression. The clinical significance of these findings for the treatment of plaque psoriasis is unknown.
A vasoconstrictor assay in healthy subjects with this lotion indicated that it is in the high to super-high range of potency as compared to other topical corticosteroids; however, similar blanching scores do not necessarily imply therapeutic equivalence. The potential for hypothalamic-pituitary-adrenal (HPA) axis suppression was evaluated in a study in adult subjects with moderate to severe plaque psoriasis. A median dose of 8.2 grams this lotion was applied once daily for 8 weeks and 20 subjects were assessed for HPA axis suppression at Weeks 4 and 8. HPA axis suppression was observed in 3 out of 20 (15%) subjects at Week 4. None of the 20 (0%) subjects had HPA axis suppression at Week 8. In this study, the criteria for HPA axis suppression was a serum cortisol level of less than or equal to 18 micrograms per deciliter 30 minutes after stimulation with cosyntropin (adrenocorticotropic hormone).