Described herein are methods of administering the anti-inflammatory drug norketotifen, an isomer, a prodrug, or a pharmaceutically acceptable salt thereof for the treatment of a respiratory disorder such as asthma and COPD in a human patient in need of such treatment, without exposing said patient to adverse immune-suppression. Dosage regimens for oral administration including a loading dosage followed by a maintenance dosage are described. Also described are methods and conditions wherein norketotifen is administered by oral inhalation. Yet, further included are methods of administering norketotifen directly to the nasal passages of the human patients in need thereof, in order to reduce or eliminate inflammatory symptoms of airways disorders, such as sinusitis, laryngitis, nasopharyngitis and various forms of rhinitis.