TRICYCLIC LACTAM COMPOUNDS, PHARMACEUTICAL COMPOSITIONS COMPRISING SAME AND THEIR USE

The invention relates to tricyclic lactams of the general formula (I) wherein Im represents an imidazolyl group of the formula: and R represents a hydrogen atom or a group selected from C1-6alkyl, C3-6alkenyl, C3-10alkynyl, C3-7cycloalkyl, C3-7cycloalkylC1-4alkyl, phenyl, phenylC1-3alkyl, phenylmethoxymethyl, phenoxyethyl, phenoxymethyl, -CO2R , -COR , -CONR R or -SO2R (wherein R and R , which may be the same or different, each represent a hydrogen atom, a C1-6alkyl or C3-7cycloalkyl group or a phenyl or phenylC1-4alkyl group, in which the phenyl group is optionally substituted by one or more C1-4alkyl, C1-4alkoxy or hydroxy groups or halogen atoms, with the proviso that R does not represent a hydrogen atom when R represents a group -CO2R or -SO2R ); one of the groups represented by R , R and R is a hydrogen atom or a C1-6alkyl, C3-7cycloalkyl, C3-6alkenyl, phenyl or phenylC1-3alkyl group, and each of the other two groups, which may be the same or different, represents a hydrogen atom or a C1-6alkyl group; n represents 2 or 3; and physiologically acceptable salts and solvates thereof. The compounds are potent and selective antagonists of the effect of 5-HT at 5-HT3 receptors and are useful, for example, in the treatment of psychotic disorders, anxiety, and nausea and vomiting.