Fuente: WIPO "tomato" The present invention provides pharmaceutical compositions comprising compounds which are selective antagonist or inverse agonist of the histamine H3 receptor, their manufacture and their use for the treatment of excessive daytime sleepiness (EDS) or cataplexy in patients with narcolepsy. Further, the present invention provides an oral liquid composition of Pitolisant or its pharmaceutically acceptable salt thereof and a process of making the same.