Accutane, with active substance Isotretinoin, a chemical cousin of vitamin A, is prescribed for the treatment of severe, disfiguring cystic acne that has not cleared up in response to milder medications such as antibiotics. It works on the oil glands within the skin, shrinking them and diminishing their output. You take Accutane by mouth every day for several months, then stop. The antiacne effect can last even after you have finished your course of medication.