Mometasone is used to control and prevent symptoms (wheezing and shortness of breath) caused by asthma. This medication must be used regularly to be effective. It does not work right away and should not be used to relieve sudden asthma attacks. If an asthma attack occurs, use your quick-relief inhaler (such as albuterol, also called salbutamol in some countries) as prescribed. Mometasone belongs to a class of drugs known as corticosteroids. It works by reducing the irritation and swelling of the airways. Controlling symptoms of breathing problems can decrease time lost from work or school.