Metoprolol succinate can be used to treat high blood pressure, angina pectoris, arrhythmia and other diseases, depending on the patient’s condition, the dosage of the drug will be different. 1. Dosage. (1) For the treatment of high blood pressure, the dosage is usually 1~2 times a day, the dosage is 100~400 mg per day. (2)For the treatment of angina pectoris, it can be taken 2~3 times a day, and the dosage is 50~100 mg per time. (3) Treatment of arrhythmia, usually taken 2~3 times a day, the total amount of roughly 50~100 mg, need to be targeted under the guidance of a doctor. 2. Adverse reactions, drug contraindications and precautions: (1) The common adverse reactions of Metoprolol succinate are mild epigastric discomfort or drowsiness. (2) People with 2nd or 3rd degree atrioventricular block and severe bradycardia should not apply, and pregnant and lactating women with hepatic or renal insufficiency need to use with caution. (3) Note that patients with bronchial asthma or in the acute stage of heart failure need to be used with caution, in the interruption of treatment, usually need to gradually reduce the drug within 7 to 10 days. During the administration of Metoprolol succinate, it is necessary to follow the doctor’s instructions for regular use of medication, master the dose of the drug, and avoid sudden discontinuation of the drug.