The present application relates to the use of 10-[(3R)-1-azabicyclo[2.2.2]oct-3-ylmethyl]-10 H -phenothiazine, 10-[(3S)-1-azabicyclo[2.2.2]oct-3-ylmethyl]-10 H -phenothiazine or 10-[(3R,3S)-1-azabicycio[2.2.2]oct-3-ylmethyl]-10H-phenothiazine or a pharmaceutically acceptable salt thereof, to prepare a drug to prevent or treat pathologies involving histamine H4 receptor, chosen among atopic dermatitis and pruritus.