Tret-Ash (Isotretinoin Capsules USP 20 mg) is a potent prescription medication primarily used to treat severe, recalcitrant nodular acne. It belongs to a class of drugs called retinoids, which are derivatives of Vitamin A. Primary Uses Severe Acne Treatment: It is specifically indicated for patients with deep, painful cysts and nodules that have not responded to other treatments, such as oral antibiotics or topical creams. Prevention of Scarring: By effectively clearing severe acne, it helps prevent permanent skin scarring and may improve long-term skin texture.