Welcome to dermatalk Abhi. Although isotretinoin can be taken along with zinc and B5, it is wise to consult the derm (that prescribed u isotretinoin). These combination will work for severe acne but sometimes make your skin severely dry, as both isotretinoin and B5 can make you skin very dry. You may give it a try, but be warned it doesn't work wonder for everyone. In addition you may also add biotin to your regimen ( so u won't have hair fall issues)