Betalox Tartrate and Betalox Succinate refer to Metoprolol Tartrate Tablets and Metoprolol Succinate Extended-Release Tablets, which are interchangeable. Metoprolol tartrate is a generic dosage form that works faster but is also metabolized more quickly, with more variable drug concentrations and unstable efficacy. Metoprolol succinate extended-release tablets are slower to release and have a slower onset of action, but are more stable. Clinically, the two drugs can be interchanged, but to master the dose, metoprolol tartrate 50mg and metoprolol succinate extended-release tablets 47.5mg similar efficacy, can play the same role. Adverse effects of metoprolol include nausea, dizziness, bradycardia, cold extremities, dyspnea, etc. It is contraindicated in patients with allergy to the drug components, cardiogenic shock, second- and third-degree atrioventricular block, and bronchial asthma. Clinical specific drug dosage form should be selected under the guidance of the physician, according to the characteristics of the patient’s condition to choose the appropriate dosage form, avoid self-medication.