The invention concerns novel substituted tetracyclic imidazole derivatives useful for the treatment of elevated intracranial pressure (ICP) and/or secondary ischaemia, in particular caused by brain injury, more in particular caused by traumatic (TBI) and non-traumatic brain injury, processes for their preparation, pharmaceutical compositions comprising them and their use as a medicine. The novel compounds comprise compounds according to the general Formula (I), the pharmaceutically acceptable acid or base addition salts thereof, the stereochemically isomeric forms thereof and the N-oxide form thereof. In particular, the preferred compound is 3-[2-[4-(11,12-dihydro-6H-benzimidazo[2,1-b][3]benzazepin-6-yl)-2-(phenyl- -l-methyl)-1-piperidinyl]ethyl]-2,10-dimethyl pyrimido[1,2-.alpha.]benzimidazol-4(10H)-one, the pharmaceutically acceptable acid or base addition salts thereof, the stereochemically isomeric forms thereof and the N-oxide form thereof. ##STR00001##