The leukotriene receptor antagonist used in bronchial asthma is:
Among the options given only Zafirleukast is leukotriene receptor antagonist. Zileuton is a 5-Lipoxygenase inhibitor, Ketotifen is an antihistaminic (H1) and Omalizumab is a recombinant humanized monoclonal anti-IgE antibody. Ref: Bronchial Asthma: A Guide for Practical Understanding and Treatment, Springer, 2011, Page 193; Current Review of Asthma, By Michael A. Kaliner - Page 216; Essentials of Medical Pharmacology, KD Tripathi - 5th Edition, Page 205-206; Katzung & Trevor's Pharmacology 10th Edition, Page 325.
Zafirleukast
Zileuton
Ketotifen
Omalizumab