Myorisan is just a generic version of Accutane, which isn't available in the US anymore. They are essentially the same and should have the same effectiveness and side effect profile (see here).

(Although a recent article has called into question their equivalency.)

Yes, I used Myorisan for three months of my course and Claravis for the last two months. Like the previous poster said, they are both generic for Accutane. I didn't notice a difference in side effects.