Is montelukast used for chronic asma & allergy?

Yes: Sigulair (montelukast) is a leukotriene receptor antagonist used for the maintenance treatment of asthma and has the added benefit of relieving symptoms of seasonal allergies. In addition, montelukast is used for other conditions including exercise induced bronchospasm, AERD, and chronic urticaria (hives).This medication is NOT useful for the treatment of acute asthma attacks.

Yes, It helps both.: Montelukast has been approved as a maintenance treatment for mild asthma and for allergic rhinitis. For asthma it is recommended to be used at night. It can also be used as a preventive for exercise induced asthma. Be careful when taking antihistamines with in at night since it can cause nightmares or "vivid dreams". There is no problem with mixing it with your Ketotifen and Escitalopram.