Keratan is loratadine. Keratan is the trade name and loratadine is the generic name or the name of the ingredient. Keratan is an anti-allergy drug that is mainly used to relieve symptoms related to allergic rhinitis, such as sneezing, runny nose, nasal congestion, nasal itching, as well as eye itching and burning sensation in the eyes. The symptoms of the nose and eyes will be relieved quickly after using the medication. Besides allergic rhinitis, Keratan can also be used to relieve chronic urticaria, itchy skin, and other allergic skin diseases. Common side effects of Keratan include causing weakness, headache, and drowsiness, as well as dry mouth and gastrointestinal discomfort, including nausea, gastritis, and skin rash. Because it is an anti-allergic drug, there is a possibility that it may interfere with the results of the skin test. Therefore, you should discontinue taking Keratan for 48 hours prior to the skin test to avoid affecting the results of the skin test.