has role has functional parent independent continuant ethyl ester pyridines retinoid tazarotene The ethyl ester of tazarotenic acid. A prodrug for tazarotenic acid, it is used for the treatment of psoriasis, acne, and sun-damaged skin. ethyl 6-[(4,4-dimethyl-3,4-dihydro-2H-thiochromen-6-yl)ethynyl]nicotinate tazaroteno Avage tazarotene ethyl 6-[(4,4-dimethyl-3,4-dihydro-2H-thiochromen-6-yl)ethynyl]nicotinate tazarotenum Tazorac Zorac keratolytic drug prodrug thiochromane teratogenic agent tazarotenic acid acetylenic compound