Isotretinoin (past brand named Accutane) will cause some profound drying of your skin as the sebaceous glands have restricted function. Undergoing a fairly aggressive procedure like Photo Dynamic Therapy at the same time could cause a hyper reaction while you are taking this drug.
Guidelines for the use of Accutane like drugs include being careful with UV exposure from any source. Your response while on Accutane to PDT could be quite severe and markedly unpleasant with some potential for scars if your skin burns excessively.
One or the other, but not both at the same time. I would not recommend this combination.



