Klm-FX 180 Tablet 10’s belongs to a class of drugs called anti-histamine or anti-allergic. It contains fexofenadine, primarily used to treat various kinds of allergies. An allergy is an immune system response to foreign elements typically not harmful to your body. These foreign elements are known as ‘allergens.’ Allergic condition varies from person to person. Some might be allergic to certain foods and seasonal allergies like hay fever. At the same time, others might be allergic to pollen or pet dander.