Nazomac M Nasal Spray is used to treat seasonal and perennial allergic rhinitis symptoms. It contains mometasone, which gets absorbed into the cells of the nasal lining and works by inhibiting these cells from releasing chemicals that trigger inflammatory and allergic reactions. Thus, it helps to relieve sneezing, runny or blocked nose, and sinus discomfort. Common side effects of Nazomac M Nasal Spray are headache, nose bleeds, sore throat or nose, sneezing, or ulcers in the nose.