This invention relates to tricyclic compounds having spiro union
represented by the following formula (I) or its salt which is useful as a
drug, and in particular, as an inhibitor for activated blood coagulation
factor X, which can be administered orally and which exhibits strong
anticoagulation action. ##STR00001## The invention also relates to a
pharmacophore which was derived from the compound and is useful in
molecular designing of the FXa inhibitor.