Consumer Drug Information

diltiazem

Generic Name: diltiazem (dil TYE a zem)
Brand names: Cardizem, Cardizem CD, Cardizem LA, Cartia XT, Dilacor XR, Diltia XT, Tiazac, ...show all 15 brand names.

What is diltiazem?

Diltiazem is in a group of drugs called calcium channel blockers. It works by relaxing the muscles of your heart and blood vessels.

Diltiazem is used to treat hypertension (high blood pressure), angina (chest pain), and certain heart rhythm disorders.

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

What is the most important information I should know about diltiazem?

Do not use this medication if you have certain heart conditions such as "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 diltiazem, tell your doctor if you are allergic to any drugs, or if you have kidney disease, liver disease, or congestive heart failure.

Diltiazem can cause side effects that may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be awake and alert. Do not stop taking this medication without first talking to your doctor. If you stop taking diltiazem 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 medication even if you feel fine. High blood pressure often has no symptoms.

What should I discuss with my healthcare provider before taking diltiazem?

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

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 diltiazem, 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.

FDA pregnancy category C. This medication may be harmful to an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant during treatment. Diltiazem can pass into breast milk and may harm a nursing baby. Do not use this medication without telling your doctor if you are breast-feeding a baby.

How should I take diltiazem?

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.

Take diltiazem with a full glass of water. Do not crush, chew, break, or open a controlled-delivery or extended-release tablet or capsule. Swallow the pill whole. It is specially made to release medicine slowly in the body. Breaking or opening the pill would cause too much of the drug to be released at one time.

If you have trouble swallowing a diltiazem 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 diltiazem regularly to get the most benefit. Get your prescription refilled before you run out of medicine completely.

Do not stop taking this medication without first talking to your doctor. If you stop taking diltiazem suddenly, your condition may become worse.

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.

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.

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.

Store diltiazem at room temperature away from moisture and heat.

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?

Seek emergency medical attention if you think you have used too much of this medicine.

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

What should I avoid while taking diltiazem?

Diltiazem can cause side effects that may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be awake and alert. Avoid drinking alcohol while taking diltiazem.

Grapefruit and grapefruit juice may interact with diltiazem 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.

Diltiazem side effects

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat. Call your doctor at once if you have any of these serious 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. Tell your doctor about any unusual or bothersome side effect. You may report side effects to FDA at 1-800-FDA-1088.

Diltiazem Dosing Information

Usual Adult Dose for Hypertension:

Initial dose: 30 to 60 mg orally 3 to 4 times a day.
Maintenance dose: 180 to 360 mg orally/day in divided doses.
SR initial dose: 60 to 120 mg orally twice a day.
SR maintenance dose: 240 to 360 mg orally/day.
CD or XR initial dose: 120 to 240 mg orally once a day.
CD maintenance dose: 240 to 360 mg orally once a day.
XR maintenance dose: 240 to 480 mg orally once a day.
LA initial dose: 120 to 240 mg orally once a day.
LA maintenance dose: 240 to 420 mg orally once a day.

IV Dosing:
Initial bolus doses: 0.25 mg/kg as a bolus administered over 2 minutes. A second bolus of 0.35 mg/kg may be used if necessary.
Initial infusion dose: 5 mg/hr.
Maintenance infusion dose: The infusion rate may be increased in 5 mg/hr increments up to 15 mg/hr.

Usual Adult Dose for Atrial Fibrillation:

Initial dose (oral): 30 to 60 mg orally 3 to 4 times a day
Maintenance dose: 180 to 360 mg orally/day in divided doses.
SR initial dose: 60 to 120 mg orally twice a day
SR maintenance dose: 240 to 360 mg orally/day.
CD or XR initial dose: 120 to 240 mg orally once a day.
CD maintenance dose: 240 to 360 mg orally once a day.
LA initial dose: 120 to 240 mg orally once a day.
LA maintenance dose: 240 to 420 mg orally once a day.

Initial dose (IV): 0.25 mg/kg actual body weight bolus over 2 minutes. If necessary, a second bolus of 0.35 mg/kg ABW may be given. In some cases, an infusion of diltiazem 5 mg/hour may be started, and advanced in 5 mg/hour increments to 15 mg/hour for up to 24 hours.

Usual Adult Dose for Atrial Flutter:

Usual Adult Dose for Supraventricular Tachycardia:

Usual Adult Dose for Angina Pectoris Prophylaxis:

Initial dose: 30 to 60 mg orally 3 to 4 times a day
Maintenance dose: 180 to 360 mg orally/day in divided doses.
SR initial dose: 60 to 120 mg orally twice a day
SR maintenance dose: 240 to 360 mg orally/day.
CD or XR initial dose: 120 to 240 mg orally once a day.
CD maintenance dose: 240 to 360 mg orally once a day.
LA initial dose: 120 to 240 mg orally once a day.
LA maintenance dose: 240 to 360 mg orally once a day.

Usual Adult Dose for Congestive Heart Failure:

Usual Pediatric Dose for not applicable:

Initial oral dose: 1.5 to 2 mg/kg/day in 3 to 4 divided doses.
Doses may be titrated to a maximum of 3.5 mg/kg/day.

What other drugs will affect diltiazem?

Before taking diltiazem, 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), fluconazole (Diflucan), itraconazole (Sporanox), ketoconazole (Nizoral), telithromycin (Ketek), 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 diltiazem. 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 diltiazem.

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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