 <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]  feel well. Most people with high blood pressure do not feel sick. For the treatment of high blood pressure, it may take 2 to 4 weeks before you get the full benefit of this drug. This medication must be taken regularly to prevent angina. It should not be used to treat angina when it occurs. Use other medications (such as nitroglycerin placed under the tongue) to relieve an angina attack as directed by your doctor. Consult your doctor or pharmacist for details. Tell your doctor if your condition worsens (for example, your chest pain worsens or your routine blood pressure readings increase).The side effects of Diltiazem Oral: Dizziness, lightheadedness, weakness, nausea, flushing, constipation, and headache may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly. To lower the risk of dizziness and lightheadedness, get up slowly when rising from a sitting or lying position. Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects. Tell your doctor right away if you have any serious side effects, including: nausea/v </s>