Patients with urticaria, especially chronic urticaria, need to adhere to the medication for a long time, some patients need to take it for 3-5 months or even 1-2 years. The side effects of antihistamines are relatively small, so you can review the blood routine, liver function and kidney function once in 1-2 months, and if there is no problem, you can take it for a long time. There are also individual patients who may experience drowsiness, dizziness and other symptoms, and other antihistamines can be adjusted. Moreover, some antihistamines are metabolized by the kidney and some by the liver, so you can choose them according to your personal situation.