Used primarily as an antihistamine to relieve allergy symptoms such as sneezing, runny nose, and itching. It is also effective in treating urticaria (hives) and other allergic skin reactions. Due to its antiserotonergic properties, it is sometimes prescribed to manage serotonin syndrome symptoms. It has appetite-stimulating effects and is used off-label to promote weight gain. Additionally, it serves as a migraine prophylactic in some patients and may be used to treat Cushing's syndrome in diagnostic settings. Its sedative effect makes it useful in managing insomnia in specific cases, though not as a first-line treatment.