Taking citalopram may cause patients to experience the side effect of drowsiness, but with the gradual reduction of the dosage or discontinuation of the drug, the symptoms of drowsiness can be relieved until it returns to the normal state. Citalopram belongs to the antidepressant drugs, may produce nausea, excessive sweating, headache, insomnia, drowsiness and other adverse reactions, usually adverse reactions are mild and temporary, such as the most frequent in the early stage of treatment, and then the reaction will gradually slow down. It is important to note that citalopram should not be discontinued abruptly, as it may produce withdrawal symptoms such as dizziness, sensory disturbances, and sleep disturbances. It is contraindicated for those who are allergic to this product and the ingredients contained in it. It is forbidden to combine with monoamine oxidase inhibitors, linezolid, pimozide and other drugs. Also use with caution in patients suffering from cardiovascular disease, renal insufficiency, suicidal tendencies, mania, history of epilepsy. Patients taking citalopram, should be used under the guidance of a professional doctor, the symptoms of drowsiness is a normal phenomenon, but if the situation is serious, it is recommended to go to the hospital for treatment.