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Diltiazem HCl oral

Important Note

The following information is intended to supplement, not substitute for, the expertise and judgment of your physician, pharmacist or other healthcare professional. It should not be construed to indicate that use of the drug is safe, appropriate, or effective for you. Consult your healthcare professional before using this drug.





This medication is a calcium channel blocker. Calcium is involved in blood vessel contraction. By blocking calcium, diltiazem relaxes and widens blood vessels. This medication is used to treat high blood pressure. High blood pressure reduction helps prevent strokes, heart attacks and kidney problems.



This medication may also be used to treat chest pain (angina) and irregular heartbeats.

How To Use

Take this medication by mouth with or without food once daily, or as directed by your doctor. Swallow the tablet whole. Do not crush or chew the tablet. Use this medication regularly in order to get the most benefit from it. To help you remember, use it at the same time each day. Do not stop taking this drug without consulting your doctor. Your condition may become worse when the drug is suddenly stopped. Your dose may need to be gradually decreased.

Side Effects

Dizziness, headache, weakness, flushing, and nausea may occur. If any of these effects persist or worsen, notify your doctor or pharmacist promptly. Tell your doctor immediately if any of these serious side effects occur: swelling of the hands or feet. Tell your doctor immediately if any of these unlikely but serious side effects occur: slow/fast/irregular heartbeat, trouble breathing, sudden weight gain, chest pain, mental/mood changes. Tell your doctor immediately if any of these highly unlikely but very serious side effects occur: stomach pain, yellowing eyes and skin, dark urine, unexplained fever. An allergic reaction to this drug is unlikely, but seek immediate medical attention if it occurs. Symptoms of an allergic reaction include: rash, itching, swelling, severe dizziness, trouble breathing. If you notice other effects not listed above, contact your doctor or pharmacist.


This medication should not be used if you have certain medical conditions. Before using this medicine, consult your doctor or pharmacist if you have: heart rhythm problems (e.g., sick sinus syndrome or second-degree or third-degree AV block without a ventricular pacemaker, ventricular tachycardia, atrial flutter or fibrillation with Wolff-Parkinson-White or Lown-Ganong-Levine syndrome), severe low blood pressure, seriously compromised heart conditions (e.g., recent heart attack with lung congestion, cardiogenic shock). Before using this medication, tell your doctor or pharmacist your medical history, especially of: other heart problems (e.g., congestive heart failure, aortic stenosis, extreme bradycardia), kidney problems, liver problems, any allergies. This drug may make you dizzy; use caution engaging in activities requiring alertness such as driving or using machinery. Limit alcoholic beverages. To minimize dizziness and lightheadedness, get up slowly when rising from a seated or lying position. Caution is advised when using this drug in the elderly because they may be more sensitive to the effects of the drug. This medication should be used only when clearly needed during pregnancy. Discuss the risks and benefits with your doctor. This medication passes into breast milk. Breast-feeding is not recommended while using this drug.

Drug Interactions

Before using this medication, tell your doctor or pharmacist of all prescription and nonprescription products you may use, especially of: amiodarone, beta-blockers (including eye drops), benzodiazepines (e.g., midazolam, triazolam), buspirone, intravenous (IV) calcium, carbamazepine, cholesterol-lowering "statin" drugs (e.g., lovastatin, simvastatin), cilostazol, cimetidine, cyclosporine, digoxin, other medications for high blood pressure or other heart conditions, quinidine, rifamycins (e.g., rifampin), St. John's wort, general surgery anesthesia. Check the labels on all your medicines (e.g., cough-and-cold products, diet aids) because they may contain ingredients that could increase your heart rate or blood pressure. Ask your pharmacist about the safe use of those products. Do not start or stop any medicine without doctor or pharmacist approval.


If overdose is suspected, contact your local poison control center or emergency room immediately. Symptoms of overdose may include: slowed or irregular heartbeat, severe weakness, fainting.


Do not share this medication with others. Have your blood pressure checked regularly while talking this medication. It may be best to learn how to monitor your own blood pressure. Discuss this with your doctor.

Missed Dose

If you miss a dose, use it as soon as you remember. If it is near the time of the next dose, skip the missed dose and resume your usual dosing schedule. Do not double the dose to catch up.


Store at room temperature at 77 degrees F (25 degrees C) away from light and moisture. Brief storage between 59 to 86 degrees F (15-30 degrees C) is permitted. Do not store in the bathroom. Keep all medicines away from children and pets.

Medical Alert

Your condition can cause complications in a medical emergency. For enrollment information call MedicAlert at 1-800-854- 1166 (USA) or 1-800-668-1507 (Canada).