Kerratan, also referred to as loratadine tablets, when used to treat urticaria, usually takes effect 30 minutes after the medication is administered, and can be maintained for 18 to 24 hours, but there is not a specific course of treatment. Loratadine tablets are mainly composed of loratadine, which is a long-acting and highly effective antihistamine drug, the drug is absorbed orally and can be effective in about 30 minutes, and the peak blood concentration is reached in about 1.5 hours, after which the effect of the drug can be maintained for 18-24 hours, and it is often used for the treatment of urticaria, as well as other allergic diseases in the clinic. Urticaria is divided into acute urticaria and chronic urticaria according to the time of onset. Acute urticaria patients usually after 1~3 days of medication, the symptoms can be controlled, stable condition can be discontinued, but also according to the changes in the condition of the appropriate extension of the treatment time. Chronic urticaria treatment time is generally longer, in the absence of particularly serious adverse reactions, need to be taken continuously for 2~4 weeks. The adverse reactions of loratadine tablets mainly include headache, drowsiness, dry mouth, fatigue and so on. Loratadine tablets are contraindicated in people who are allergic to the drug ingredients, and patients with severe liver or kidney insufficiency need to use with caution. In order to ensure the safety and effectiveness of the medication, it is important to strictly follow the doctor’s instructions.