TOPROL-XL^® (metoprolol succinate) is an extended-release tablet that belongs to a family of high blood pressure medications known as beta-blockers. TOPROL-XL extended-release tablets need to be taken only once a day. After swallowing, the coating of the tablet dissolves, releasing hundreds of pellets filled with medication. These pellets slowly disintegrate in your digestive tract, delivering medicine to your body, where it works for 24 hours.