Centair-AX is a combination of three medicines usually prescribed for the prevention of Asthma. Ambroxol is a mucolytic which thins and loosens mucus (phlegm), making it easier to cough out. Levocetirizine is an antiallergic which relieves allergy symptoms like runny nose, watery eyes and sneezing. Montelukast is a leukotriene antagonist. It works by blocking the action of leukotriene, a chemical messenger. This reduces inflammation in the airways and nose and improves your symptoms.