Generic Claritin functions by decreasing the levels of histamine substances that are secreted by the immune system of victim's body, which lead to symptoms such as sneezing, runny nasal passage, itches, and watery eyes. The first action of the drug is to prevent the succession of allergic reactions. Its active constituent enhances the functions of the immune system against the allergen. In the subsequent step it truncates the symptoms of the allergies. The action mechanism of the drug is dissimilar than other anti-allergic drugs, as it has no influence on the central nervous system. One can take this medicine in general as well; however, it is suggested to check with the doctor prior to taking the pill.