 <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]  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 times each day. Keep taking this medication even if you feel well. Most people with high blood pressure do not feel sick. If this medication is used for angina, this medication must be taken regularly to be effective. 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. It may take up to 2 weeks before you get the full benefit of this drug. Tell your doctor if your condition lasts or gets worse (for example, your routine blood pressure readings remain high or 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 </s>