It is indicated for the treatment of severe recalcitrant nodular acne. The usual adult and adolescent dose is 0.5 to 1 mg/kg of body weight per day (in two divided doses) for 15 to 20 weeks; the maximum recommended dose is 2 mg/kg of body weight per day and may be required in patients whose disease is very severe or is primarily located on the chest or back instead of on the face. During the initial period of isotretinoin therapy, transient exacerbation of acne may occur; concomitant adrenocorticoid therapy may be required