4 - fluoro - 4 - phenylpiperidin - 1 - yl μ antagonists of general structure as well as pharmaceutical compositions comprising compounds of formula i , are disclosed . these compounds and compositions are useful as treatments of conditions or diseases associated with binding opioid receptors including pain , obesity , hyperalgesia , inflammation , osteoarthritis , drug addiction , and cancer . these compounds and compositions are also useful as treatments for tardive dyskinesia .