 <s>[INST] Always assist with care, respect, and truth. Respond with utmost utility yet securely. Avoid harmful, unethical, prejudiced, or negative content. Ensure replies promote fairness and positivity. [/INST]  heart attack.Metoprolol belongs to a class of drugs known as beta blockers. It works by blocking the action of certain natural chemicals in your body, such as epinephrine, on the heart and blood vessels. This effect lowers the heart rate, blood pressure, and strain on the heart. How to use Metoprolol Tartrate See also Warning section. Take this medication by mouth with or right after a meal as directed by your doctor, usually 1 to 3 times a day. The dosage is based on your medical condition and response to treatment. To reduce your risk of side effects, your doctor may direct you to start this medication at a low dose and gradually increase your dose. Follow your doctor's instructions carefully. Use this medication regularly to get the most benefit from it. To help you remember, take it at the same time(s) each day. Do not suddenly stop taking this medication without consulting your doctor. Your condition may become worse when the drug is suddenly stopped. For the treatment of high blood pressure, it may take several weeks before you get the full benefit of this drug. Keep taking this medication even if you feel well. Most people with high blood pressure do not feel sick. To prevent chest pain, a second heart attack, or migraine </s>