The invention concerns a novel histamine receptor antagonist and the use of an histamine receptor antagonist for the reduction of intracranial pressure (ICP), in particular for the prevention and treatment of elevated intracranial pressure and/or secondary ischaemida, in particular caused by brain injury, more in particular caused by traumatic (TBI) and non-traumatic brain injury. 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- -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. Also claimed is the novel use of commercially available histamine H1-and H2-receptor antagonists for the reduction of intracranial pressure (ICP). ##STR00001##