Is Accutane One Times 20mg Tablet Once a Week Toxic?

hi I took a full course of Accutane 4 years ago for severe seborrhoea and bad acne seborrhoea returned although no way near as bad, i am looking into trying Accutane ultra low dose is this safe besides the pregnancy issues, im more concerned with liver damage etc, can this dose be taken continuously , thanku Leanne :)