How effective is singulair (montelukast) for shortness of breath in chest from asthma? is it fast working?

Singulair (montelukast) not fast.: Singular is not meant for the acute treatment of acute shortness of breath related to asthma. It's a maintenance medications, meant to be taken once daily for symptom control and for prevention of asthma attacks. It will not help in an asthma attack if taken right then and there. You'd really need an Albuterol pump and a short course of steroids.

Singular and asthma: Singulair or montelukast cannot be used for acute asthma as it is slow to work and not everyone responds to it. It needs to be taken every day to work. Reliever ( blue ) pumps are best when you are short of breath . Singular can be used in addition to prevention ( brown/orange ) pumps if someone continues to get wheezing.

Quite effective: First you have to address what are the triggers for your asthma and if at all possible try to reduce or eliminate them from your environment. Is your asthma brought on by cold weather or a cold (infection) or an allergy (clean up your house and get a HEPA filter) or exercise (take med prophylactically). Singulair (montelukast) (a leukotriene receptor antagonist) acts on one branch to cause bronchodilation.