Accutane is usually dosed in such a way as to reach an average of 1.0 mg/kg to 1/5 mg/kg daily over the six months of treatment. Doses significantly lower than this result in fewer cures and more recurrences after the treatment is finished.
I usually recommend starting at 20 mg daily and going up in dose every month to reach an average of 1.0-1.5 mg/kg/day.
The safety depends on your body's response to the medication. Some side effects are controllable, some are not. Hair loss (telogen effluvium in this case) usually results in discontinuation of the medication in my practice, as I find that going to a lower dose does not make that subside.
If the cholesterol goes up, I review the diet with the patient and make sure that all saturated fats and simple carbohydrates, like bread, potatoes, rice, pasta, sweets, etc are discontinued. That usually halts the increases in cholesterol.
Certain side effects would cause me to discontinue Accutane, like liver function abnormalities, decreases in the white blood cell count, severe mood swings.
It is fine to take low dose Accutane as long as one is aware that low dose Accutane rarely results in a cure of acne and needs to be continued indefinitely to maintain the results.