Adapalene is a topical drug that is primarily used to treat moderate to severe acne. It works by reducing inflammation and swelling of the skin, as well as by affecting the growth of skin cells. Adapalene belongs to the class of medicines known as retinoids, which helps the skin to rebuild and renew itself. By stimulating the growth of new skin cells, Adapalene helps to prevent the formation of acne lesions and promotes the healing of existing ones.