Chronic itching & fissure in perianal area, tried fluzan, doxepin, trental (pentoxifylline) pills & mycoster, cicalfate creams nothing worked. Any new stuff other cures?

Psoriasis? Perianal psoriasis, lichen planus and other derm conditions can occur, lead to some of the above. May not be primary fissure, or fungal (what you have been rx'd for based on med list). Unlikely std, but if that is a consideration, then it is a consideration. See derm, maybe GI or colorectal surgeon afterward.
Get evaluated. See a colorectal surgeon for proper diagnosis. The most worrisome thing this could be is a skin cancer in that region. If it is just really bad itching inthat area (which does happen), and other topical treatments don't help, capsaicin cream may help.