Metoprolol is a short-acting beta-blocker and should normally be taken in a twice-a-day dose, not once a day. However, metoprolol is available in an extended-release formulation as Betalucil extended-release tablets, which can be given as a once-a-day dose. Metoprolol is a beta-blocker and has antiarrhythmic and antihypertensive effects. Metoprolol is a short-acting agent that cannot maintain a smooth antiarrhythmic and antihypertensive effect 24 hours a day, and is recommended to be taken twice a day or more. For patients with coronary artery disease and acute coronary syndromes who often need to titrate beta-blockers, a method of titrating metoprolol flat tablets every six hours to reach the target dose and then replacing it with an extended-release preparation can be given to better regulate the state of cardiac function.