Diltiazem belongs to a class of medications called calcium-channel blockers. It works by relaxing the blood vessels so the heart does not have to pump as hard. Diltiazem also increases the supply of blood and oxygen to the heart.

Diltiazem oral is used in adults alone or in combination with other medicines to treat hypertension (high blood pressure) or symptoms of angina (chest pain). Lowering blood pressure may lower your risk of a stroke or heart attack.

Diltiazem injection is used in adults to treat certain heart rhythm disorders such as atrial fibrillation or atrial flutter, or dangerously rapid heartbeats (tachycardia).

You should not use diltiazem if you have very low blood pressure, a serious heart condition such as "sick sinus syndrome" or "AV block" (unless you have a pacemaker), or if you have recently had a heart attack and you have a build-up of fluid in your lungs.

Before taking this medicine, tell your doctor if you have kidney disease, liver disease, or congestive heart failure.

Diltiazem may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be alert. Do not stop taking this medication without first talking to your doctor. If you stop taking it suddenly, your condition may become worse.

Diltiazem 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 medicine even if you feel well. High blood pressure often has no symptoms. You may need to use blood pressure medicine for the rest of your life. However, if you have symptoms of low blood pressure (dizziness, fainting, weakness, or blurred vision), call your doctor and stop taking diltiazem.

Diltiazem comes as a tablet, an extended-release (long-acting) tablet, and an extended-release capsule to take by mouth. The regular tablet is usually taken three or four times a day. The extended-release capsule and tablet are usually taken one or two times a day. Ask your pharmacist if you should take diltiazem with or without food, because instructions may vary with each product. Take diltiazem at around the same time(s) every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take diltiazem exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Swallow the extended-release capsules and tablets whole; do not chew or crush them.

Your doctor will probably start you on a low dose of diltiazem and gradually increase your dose, not more than once every 7 to 14 days if you are taking the extended-release tablet or capsule and not more than once every 1 to 2 days if you are taking the regular tablet.

If taken regularly, diltiazem may control chest pain, but it does not stop chest pain once it starts. Your doctor may give you a different medication to take when you have chest pain.

Diltiazem controls high blood pressure and chest pain (angina) but does not cure them. It may take up to 2 weeks before you feel the full benefit of diltiazem. Continue to take diltiazem even if you feel well. Do not stop taking diltiazem without talking to your doctor.

Use diltiazem exactly as prescribed by your doctor. Follow all directions on your prescription label and read all medication guides or instruction sheets. Your doctor may occasionally change your dose.

Diltiazem injection is given into a vein by a healthcare provider. Your heart rate will be constantly monitored using an electrocardiogram or ECG (sometimes called an EKG). Your blood pressure and other vital signs will also be watched closely.

Diltiazem oral is taken by mouth. Your pharmacist can provide more information about how to take this medicine correctly.

Your dose needs may change if you switch to a different brand, strength, or form of this medicine.

Some forms of diltiazem oral cannot be crushed or chewed, and some forms can be opened and mixed with applesauce. Ask your pharmacist how to take this medicine.

Your blood pressure and liver function will need to be checked often.

If you have high blood pressure, keep using this medicine even if you feel well. High blood pressure often has no symptoms.

Store at room temperature away from moisture, heat, and light.

You should not use diltiazem if you are allergic to it, or if you have:

• a serious heart condition such as "sick sinus syndrome" or "AV block" (unless you have a pacemaker);

• very low blood pressure;

• if your heart cannot pump blood properly; or

• if you have recently had a heart attack and you have a build-up of fluid in your lungs.

You may not be able to use diltiazem if you have:

• heart failure;

• certain heart rhythm disorders (such as 'Afib' or atrial flutter with Wolff-Parkinson-White syndrome);

• a heart condition that causes you to have very fast heartbeats; or

• if you are receiving an intravenous beta-blocker (such as atenolol, metoprolol, or propranolol).

To make sure this medicine is safe for you, tell your doctor if you have ever had:

• congestive heart failure or heart problems;

• low blood pressure or slow heart rate; or

• liver disease.

It is not known whether diltiazem will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.

Tell your doctor if you are breastfeeding.

Diltiazem injection is used when needed and does not have a daily dose. Call your doctor if the medicine is not effective.

Take diltiazem oral as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Overdose symptoms may include low blood pressure, slow heart rate, severe dizziness, or fainting.

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom).

It is important to keep all medication out of sight and reach of children as many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location – one that is up and away and out of their sight and reach. http://www.upandaway.org

Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA's Safe Disposal of Medicines website (http://goo.gl/c4Rm4p) for more information if you do not have access to a take-back program.

If your doctor prescribes a low-salt or low-sodium diet, follow these directions carefully.

Avoid drinking alcohol while taking diltiazem extended-release capsules. Drinking alcohol with this medicine can cause side effects.

Avoid taking an herbal supplement containing St. John's wort.

Avoid getting up too fast from a sitting or lying position, or you may feel dizzy. Avoid driving or hazardous activity until you know how this medicine will affect you. Your reactions could be impaired.

Get emergency medical help if you have signs of an allergic reaction to diltiazem (hives, difficult breathing, swelling in your face or throat) or a severe skin reaction (fever, sore throat, burning eyes, skin pain, red or purple skin rash with blistering and peeling).

Diltiazem may cause serious side effects. Call your doctor at once if you have:

• chest pain, fast, slow, or uneven heart rate;

• a light-headed feeling, like you might pass out;

• heart problems - swelling, rapid weight gain, feeling short of breath; or

• liver problems - loss of appetite, stomach pain (upper right side), tiredness, itching, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes).

Common diltiazem side effects may include:

• swelling;

• infections, flu symptoms;

• trouble breathing;

• headache, dizziness, weakness;

• slower heart rate;

• pain, bruising, swelling, or irritation where the medicine was injected;

• nausea, upset stomach; or

• rash.

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.

Sometimes it is not safe to use certain medicines at the same time. Some drugs can affect your blood levels of other drugs you use, which may increase side effects or make the medicines less effective.

Many drugs can interact with diltiazem. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed here. Tell your doctor about all other medicines you use.

Keep all appointments with your doctor and the laboratory. Your blood pressure should be checked regularly to determine your response to diltiazem.

Your doctor may ask you to check your pulse (heart rate) daily and will tell you how fast it should be. If your pulse is slower than it should be, call your doctor for directions on taking diltiazem that day. Ask your doctor or pharmacist to teach you how to check your pulse.

Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.

This medicine could take a couple of weeks to work fully.

If you’re using diltiazem for high blood pressure, you may not have symptoms or notice any changes while on treatment. This doesn’t mean it isn’t working. Don’t stop taking diltiazem without first talking to your doctor.

You may have to take diltiazem for a long time, possibly even the rest of your life.

Your dose will depend on your medical condition, age, the formulation you use, and other factors.

Take this medicine exactly as your doctor prescribes.

Diltiazem is sometimes used to treat or prevent other medical conditions, such as cluster migraines or anal fissures.

• Teczem® (containing Diltiazem, Enalapril)