or substantially pure isomeric form e g greater than 70 enantiomeric diastereomeric excess u201c ee u201d preferably greater than 80 ee more preferably greater than 90 ee most preferably greater than 95 ee the purification of said isomers and the separation of said isomeric mixtures may be accomplished by standard techniques known in the art e g column chromatography preparative tlc preparative hplc simulated moving bed and the like geometric isomers by nature of substituents about a double bond or a ring may be present in cis z or trans e form and both isomeric forms are encompassed within the scope of this invention compounds of the invention may in some cases also exist in prodrug form the term u201c prodrug u201d is an art recognized term and refers to a drug precursor prior to administration but generates or releases the active metabolite in vivo following administration via some chemical or physiological process in some instances the compounds of the invention may be a prodrug as well as a metabolite our inventors have found that by blocking the in vivo back formation of the active 1 4 fluoro phenyl 4 6br 10as 3 methyl 2 3 6b 9 10 10a hexahydro 1h 7h pyrido 3 u2032 4 u2032 4 5 pyrrolo 1 2 3 de quinoxalin 8 yl butan 1 one the compounds of the invention would prevent dopamine antagonism while maintaining binding to 5 ht 2a and sert wherein x is u2014 n ch.