Depends how big you are and how bad your acne is.
I had bad acne and I am 225 lbs. I am currently taking 80mg/day. I just finished my fourth month.
One cycle of accutane generally lasts for 5-6 months and dosages range from 40mg/day-80mg/day.
Send me a PM along with a description of your size/severity of acne and I will see if I can help you.
Good Luck!!!