Diltiazem is a drug that is used for treating heart pain (angina), high blood pressure, and abnormal heart rhythms. It belongs to a class of drugs called calcium channel blockers (CCBs), which includes amlodipine (Norvasc), verapamil (Calan, Isoptin), nifedipine (Adalat, Procardia) as well as others. CCBs block the entry of calcium into muscle cells that make up the heart and that surround the arteries. It is the entry of calcium into these cells that causes the cells to contract, allowing the heart to pump blood, and the arteries to narrow. By blocking the entry of calcium, diltiazem decreases the force of contraction of the heart and its rate of contraction. It also relaxes the muscles surrounding the arteries, allowing the arteries to widen (dilate). In order to pump blood, the heart needs oxygen. The harder the heart works, the more oxygen it requires. Angina occurs when the supply of oxygen to the heart is inadequate for the amount of work the heart must do. By dilating arteries, diltiazem reduces the pressure in the arteries into which the heart must pump blood, and, as a result, the heart needs to work less and requires less oxygen. By reducing the heart's need for oxygen, diltiazem relieves or prevents angina. Dilation of the arteries also reduces blood pressure. The FDA approved diltiazem in 1982.

What is Cardizem?

Cardizem is in a group of drugs called calcium channel blockers. It works by slowing the electrical conduction in the heart, slowing heart rate, and/or normalizing heart rhythm.

Cardizem is used to treat hypertension (high blood pressure), angina pectoris (chest pain), and certain heart rhythm disorders (supraventricular tachycardia, atrial fibrillation).

Cardizem may also be used for other purposes not listed in this medication guide.

Important information about Cardizem

Before taking Cardizem, tell your doctor if you are allergic to any drugs, or if you have kidney disease, liver disease, or congestive heart failure.

Cardizem may be only part of a complete program of treatment that also includes diet, exercise, and other medications. Follow your diet, medication, and exercise routines very closely.

If you are being treated for high blood pressure, keep using this medication even if you feel fine. High blood pressure often has no symptoms.

Before taking Cardizem

• certain heart conditions, especially "sick sinus syndrome" or "AV block" (unless you have a pacemaker);

• low blood pressure; or

• if you have recently had a heart attack.

Before taking Cardizem, tell your doctor if you are allergic to any drugs, or if you have:

• kidney disease;
• liver disease; or

• congestive heart failure.

If you have any of these conditions, you may need a dose adjustment or special tests to safely take this medication.

How should I take Cardizem?

Take this medication exactly as it was prescribed for you. Do not take the medication in larger amounts, or take it for longer than recommended by your doctor. Follow the directions on your prescription label.

Your doctor may occasionally change your dose to make sure you get the best results from this medication.

If you have trouble swallowing a Cardizem capsule whole, ask your doctor or pharmacist if it is safe for you to open the capsule and sprinkle the medicine into a spoonful of applesauce to make swallowing easier. Swallow this mixture right away without chewing. Do not save the mixture for later use. Discard the empty capsule.

It is important to use Cardizem regularly to get the most benefit. Get your prescription refilled before you run out of medicine completely.

If you are being treated for high blood pressure, keep using this medication even if you feel fine. High blood pressure often has no symptoms.

Cardizem may be only part of a complete program of treatment that also includes diet, exercise, and other medications. Follow your diet, medication, and exercise routines very closely.

To be sure this medication is helping your condition, your blood pressure will need to be tested on a regular basis. Your kidney and liver function may also need to be tested. Do not miss any scheduled visits to your doctor.

What happens if I miss a dose?

Take the missed dose as soon as you remember. However, if it is almost time for the next dose, skip the missed dose and take only the next regularly scheduled dose. Do not take a double dose of this medication.

What happens if I overdose?

Overdose symptoms may include slow heartbeat, weakness, chest pain, shortness of breath, feeling light-headed, or fainting.

What should I avoid while taking Cardizem?

Grapefruit and grapefruit juice may interact with Cardizem and lead to potentially dangerous effects. Discuss the use of grapefruit products with your doctor. Do not increase or decrease the amount of grapefruit products in your diet without first talking to your doctor.

Cardizem side effects

• fast or slow heartbeats;

• feeling light-headed, fainting;

• fever, sore throat, and headache with a severe blistering, peeling, and red skin rash;

• feeling short of breath, even with mild exertion;

• swelling, rapid weight gain; or

• nausea, stomach pain, low fever, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes).

Less serious side effects may include:

• stuffy nose;

• skin rash or itching;

• dizziness, headache, tired feeling;

• nausea; or

• warmth, itching, redness, or tingly feeling under your skin.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What other drugs will affect Cardizem?

Before taking Cardizem, tell your doctor if you are using any of the following drugs:

• amiodarone (Cordarone, Pacerone);

• buspirone (BuSpar);

• carbamazepine (Carbatrol, Tegretol);

• cimetidine (Tagamet, Tagamet HB);

• cyclosporine (Gengraf, Neoral, Sandimmune);

• digoxin (digitalis, Lanoxin, Lanoxicaps);

• lovastatin (Mevacor);

• rifampin (Rifadin, Rimactane, Rifater);

• quinidine (Quinaglute, Quinidex, Quin-Release);

• a sedative such as midazolam (Versed) or triazolam (Halcion);

• an antibiotic such as clarithromycin (Biaxin), erythromycin (E-Mycin, E.E.S., Ery-Tab, Erythrocin) or telithromycin (Ketek);

• an antifungal medication such as fluconazole (Diflucan), itraconazole (Sporanox), ketoconazole (Nizoral), or voriconazole (Vfend);

• a beta-blocker such as atenolol (Tenormin), bisoprolol (Zebeta, Ziac), metoprolol (Lopressor, Toprol), propranolol (Inderal, InnoPran), sotalol (Betapace), timolol (Blocadren), and others; or

• HIV/AIDS medicine such as amprenavir (Agenerase), atazanavir (Reyataz), delavirdine (Rescriptor), fosamprenavir (Lexiva), indinavir (Crixivan), nelfinavir (Viracept), or ritonavir (Norvir, Kaletra).

This list is not complete and there may be other drugs that can interact with Cardizem. Tell your doctor about all the prescription and over-the-counter medications you use. This includes vitamins, minerals, herbal products, and drugs prescribed by other doctors. Do not start using a new medication without telling your doctor.

Where can I get more information?

• Your pharmacist can provide more information about Cardizem.

• Remember, keep this and all other medicines out of the reach of children. Never share your medicines with others and only use this medication for the condition prescribed.
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