As far as I concern this drug have been widely studied base on 0.5mg/kg 1mg/kg of human bodies.

Let say you are 70kg you should consume around 70mg daily for it to be effective. However local dermatologist(Malaysia) are only prescribing around 20mg daily. Hence I believed its going to be pretty safe.

You should only avoid using this drug only if you plan to have babies within 1month. (Applicable to woman)