 <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] . Follow your doctor's instructions carefully. The dosage is based on your medical condition, response to treatment, and other medications you may be taking. Be sure to tell your doctor and pharmacist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products). Use this medication regularly to get the most benefit from it. To help you remember, use it at the same time each day. Keep taking this medication even if you feel well. Most people with high blood pressure do not feel sick. For the treatment of high blood pressure, it may take 2 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 </s>