Disclosed is a piperazine or diazapane compound of formula (I) where the substituents are as disclosed and examples of the compounds are: ( 4-Isopropyl-piperazin-1-yl)-[6-(tetrahydro-furan-3-yloxy)-pyridin-3-yl]-methanone (4-lsopropyl-[1,4]diazepan-1-yl )-[6-(tetrahydro-furan-3-yloxy)-pyridin-3-yl]methanone and (4-Cyclopropyl-[ 1,4]d iazepan-1-yl )-[6-(tetrahydro-furan-3-yloxy)-pyridin-3-yl]methanone. Also disclosed is a pharmaceutical composition comprising a compound of formula (I) and the use of a compound of formula (I) in the manufacture of a medicament for the treatment of a diseases or condition mediated by histamine H3 receptor activity. Examples of diseases and conditions are depression, disturbed sleep, fatigue, lethargy, cognitive impairment, memory impairment, memory loss, learning impairment, attention-deficit disorders, and eating disorders
