Ratino A - Tretinoin Cream USP is used to treat acne. It may decrease the number and severity of acne pimples and promote quick healing of pimples that do develop. It contains tretinoin, which is an active metabolite of Vitamin A that binds to intracellular receptors and modifies the way skin cells behave. Tretinoin belongs to a class of medications called retinoids. This medicine is a keratolytic medication that prevents formation of new pimples and blackheads by blocking the hardening processes of the outer skin layer.