5-HT3 receptor antagonists

A method of treating a nicotine addiction comprising:

• administrating to a patient in need thereof a therapeutically effective amount of a compound of the formula
• wherein:
• Z is O or NRa where Ra is hydrogen or C1-6 alkyl;
• R1 is a ring of the formula (a)-(h) below:
• R2 is hydrogen, C1-6 alkyl, or C1-6 haloalkyl;
• each R3 is independently hydrogen, C1-6 alkyl, C1-6 alkoxy, C1-6 haloalkoxy, or halo and can be present on any carbon atom in the rings;
• R4 is pyridinyl or pyrazolyl each optionally substituted with one or two substituents independently selected from C1-6 alkyl, C1-6 haloalkyl, C1-6 haloalkoxy, C1-6 alkoxy, cyano, or halo;
• all of X1, X2, X3, and X4 are CR5;
• each R5 is independently hydrogen, C1-6 alkyl, halo, hydroxy, or cyano provided that at least one of R5 is hydrogen;
• X5 is CR6 where R6 is hydrogen, C1-6 alkyl, or halo;
• or a pharmaceutically acceptable salt thereof or N-oxide thereof.