The most common dosage regime involves starting with a low dose, then increasing the dose after several weeks. The length of the treatment course varies but generally lasts from 16 to 20 weeks.
Some people notice that their acne initially gets worse after starting isotretinoin therapy. The number of acne lesions usually does not increase, but the lesions may become redder or more painful. This is normal and lasts only for a short while. This is not a reason to stop using isotretinoin.